Safc Hitech Insight Newsletter - March 2009

Insight A regular update to the semiconductor industry

March 2009

SAFC Hitech® and AWI Strengthen Long Term Research Collaboration SAFC Hitech and Air Water Inc. (AWI) have a long history working together to develop and provide performance chemicals to both the silicon and compound semiconductor markets in

Page 2 2008 in Review Page 3 Customer Satisfaction Survey Results Page 4 Halide Mediated Improvement of Lateral Growth of InN in MOCVD

Japan. Molecular engineering of compounds to tailor physical properties is an involved process that relies heavily on source assessment under actual usage conditions. The correlation of performance results in a deposition process to novel chemistry highlighting

Page 6 REACH Pre-registration Accomplished

beneficial changes is used to ensure continuous improvement in precursor performance. Obviously layer growth and characterisation capabilities must be to the highest standards and in the last 12 months long-term plans have been established

A Focus on Procurement in a Global Supply Chain

to provide high quality research and development facilities to support the needs of the end user Integrated Device

Page 7 Tungsten Carbonitride Thin Films

Manufacturer (IDM) and Original Equipment Manufacturer (OEM) in Japan. It is essential that a locally available fast and responsive reaction to their research needs is

Page 8 Improved Processes and Materials for Energy Saving Glazing

accessible as they develop new integrated circuits and the tools to build them for the rapidly expanding market for state-of-the-art electronic semiconductor devices. AWI’s central research facility is located at Matsumoto in the Nagano prefecture of Japan and a wide range of high purity gas and chemical related research is performed under the

New Regulations for Certification of Containers

directorship of Hirohisa Hiramatsu. Within this facility there are laboratories and clean rooms where SAFC Hitech and AWI together investigate the performance of new chemicals required by the semiconductor industry. The inclusion of electrical measurement equipment along with deposition tools allows the researcher to establish I-V and C-V plots and thus establish the flow of current (or not) through the surface of the grown films and their substrates

Page 9 Crystal Grade Metal Halides Make Big Impact Geoff Irvine Expanded Role

all in one centre of excellence. Such superb facilities have attracted a number of Japanese multinational IDMs and OEMs to send their research engineers to Matsumoto to work alongside our researchers on specific projects under

Page 10 Cadmium Oxide as an Alternative TCO

strict non-disclosure agreements. Continued on page 5

Page 11 Conference Representation 2009 Page 12 Contact Details

www.safchitech.com

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SAFC Hitech News

2008 in Review - Barry Leese 2008 was an extremely successful year for SAFC Hitech with significant growth achieved despite the downturn in general economic conditions during the latter stages of the year. As well as increasing our revenues, we continued to invest in several areas: in expanding our manufacturing footprint in growth opportunity areas; in the development of new and innovative materials; and in the equipment with which these materials can be delivered to the process chamber most effectively. During the year several effective campaigns have emphasised our ongoing commitment to leadership in the compound semiconductor market, expanded our presence in the silicon semiconductor area and also entered into numerous emerging markets for ‘performance’ or ‘specialist’ chemicals where we see substantial future business opportunities. Investment in production facilities has seen the opening of our $9 million 5000ft² cleanroom at Sheboygan, Wisconsin along with commissioning of additional plant capacity at Bromborough, Haverhill and Taiwan. These expansions enable us to produce, package and analyse products in multiple locations in higher volumes, completing the total supply chain to ensure our customers an uninterrupted supply of the highest quality materials globally. We hosted extremely successful media visits to both the Sheboygan and Bromborough facilities in 2008. These visits not only gave us a chance to update our friends in the editorial community about our ongoing investment program but also an opportunity to qualify these investments in tangible terms by actually showing them around the expanded facilities. Furthermore product developments were highlighted to demonstrate the advances made in precursor technologies by our highly active Research team. In particular novel materials for Germanium Antimony Telluride (GexSbyTez or GST) for use in high volume manufacturing phase change memory (PCM) applications generated significant interest from several very large customers. In October we announced the availability of our portfolio of Crystal Growth Halides representing the first launch from the ‘Performance Materials’ range of SAFC Hitech. This new element of product offerings focuses on applications outside the “standard” Compound and Silicon areas to enhance our ability to service a wider range of customers in the electronics and related industries. The rapidly-developing solar market falls into this category with sol-gel, chemical bath deposition (CBD) and other techniques as well as CVD requiring HVM of high quality chemicals. We are already seeing major requirements for materials for CBD CIGS (copper indium gallium selenide) and CdTe/CdSe (cadmium telluride/selenide) to complement the existing range of CVD precursors. III-V and Si CVD sources complete the SAFC Hitech ability to supply precursors to all the conventional competing technologies and future investment in the organic electronics area will ensure full coverage of future fabrication methods. In addition to expanding our product range we have developed our equipment offering to enhance the delivery of precursors to the deposition equipment. The introduction of the OM700, a bubbler that offers customers a cost-efficient migration path to controlled precursor delivery for larger lot sizes, and the EpiVapor™, a cost-effective metalorganic vapour phase distribution system that eliminates the need for localised tool bubblers and TCUs by delivering vapours from highly volatile and sensitive pyrophoric liquids directly to MOCVD systems, has been very well received in the market place. These enabling technologies afford a reduction in process downtime and increased safety controls. Looking forward to 2009, we aim to maintain our highest standards of service to an expanding compound and silicon semiconductor industry, to invest in locations and technologies that we feel will enhance our capabilities in emerging areas such as photovoltaics, and to provide a stable supply chain to all of our customers.

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Customer Satisfaction Survey Results SAFC Hitech strives to achieve the highest standards of customer service and to assess performance in this area conducts an annual survey to allow customer perceptions to be evaluated. Feedback is highly valued and numerous improvement projects have been implemented based on this customer input. The objective is always to maintain our highly valued relationship with product users and ensure all areas of the SAFC Hitech/customer Overall Rating interface remain at the highest level. SAFC Hitech would like to thank all of the respondees for their time and comments which will be used to improve our performance. A prize draw was held for all completed forms and this year’s winner of a state-of-theart iPod is Tom Katona in USA. The findings of the survey allow corrective actions to be established to counter negative experiences as well as ensuring newly introduced protocols are successful. Positive feedback demonstrates that dealing with SAFC Hitech has met or surpassed customer expectations.

Are there specific products required to be introduced?

How do you rate the website?

Overall this year the majority of responses were positive with an increased ratio compared to negative items indicating the already excellent perception of SAFC Hitech as a precursor supplier from previous years has been improved upon. Last year’s issue relating to the communication of the change from Epichem to SAFC Hitech has been resolved and the new brand has become widely recognised as a premier precursor supplier across an increasingly wide range of application technologies. This expansion in remit for SAFC Hitech may explain the comments received relating to a customer requirement for more products to meet their needs. The SAFC Hitech research team is highly active to develop new materials to meet these demands. Due to the range of chemicals involved and the volumes, their introduction to the full catalogue does take time hence specific technical contact with customers is employed to disseminate new offer areas. Further efforts to exhibit the full range of capabilities to supply compounds specifically matched to customer processes in an ad-hoc manner suited to new material process development are planned for the coming months to address this lack of communication. Again it should be stressed that those customers dealing with the Technical team were highly appreciative of the support and this service is to be further highlighted for new customers to access and discuss alternative precursor strategies. In recent months the upgraded website has improved the availability of technical data on standard products and continuous assessment is performed to maintain and update this database of precursor properties. As in previous years customers who returned negative comments will be contacted directly by their account manager to discuss these concerns and determine a strategic plan to resolve any difficulties. A key target for 2009 will be to maintain effective communications between all our customer and SAFC Hitech contacts in Sales, Customer Services, Technical Services and beyond. Coupled with the planned improvements to product offer communications we hope to demonstrate the extensive options available to all customers to ensure purchase of the precursors best suited to their processes in the most efficient manner.

Positive Negative

Detailed Results Are orders dealt with and delivered as promised?

Are you satisfied with the level of service from the technical support team?

Are you satisfied with the level of service from the customer service team?

Is product packaging and safety information to standard?

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SAFC Hitech News

Halide Mediated Improvement of the Lateral Growth of InN in MOCVD Recently, a lot of research efforts have been devoted to InN, the least known of the semiconducting group-III nitrides. The growth using the Molecular Beam Epitaxy (MBE) technique has been more investigated, while fewer studies used the Metal Organic Vapor Phase Epitaxy (MOVPE) method. Whatever the approach, the growth of InN has proved extremely challenging; in particular due to the fact that no lattice matched substrate is available. In this work, we present our results regarding the progress in MOVPE growth of InN achieved in the INDOT project thanks to inputs from all partners to optimise materials and processes (see inset for INDOT details or www.indot-project.net). First, we attempted to reproduce the MOCVD technology for production of successful two-step growth method which is commonly used to form indium nitride based nanophotonic devices epitaxial GaN layers on a sapphire substrate, also with a large lattice mismatch. In-depth analysis of the structure and morphology of a GaN Participant name Country nucleation layer in order to transpose this knowledge to the AIXTRON AG Germany InN/GaN/sapphire system was performed. The detailed study of such an annealed GaN buffer revealed the presence of a typical density of GES UMR5650 CNRS France 1011 per cm2 crystal grains, with a quality analysed by grazing X-ray diffraction that showed a full width at half maximum of 3600 arcseconds SAFC Hitech Limited UK for the (10-10) diffraction peak. Such a test structure was produced SAES Getters SpA Italy using the required low temperature MOVPE growth of InN on sapphire, however, it was not possible to obtain high crystal quality due to the lack of surface mobility and lateral growth, which limits the coalescence of InN during growth. Due to the restriction of thermal energy that can be inputted to the InN system to avoid product evaporation during growth, a novel chemical approach has been studied to enhance surface mobilities and allow high quality films to be deposited. This technique involves modification of the gas phase chemistry to enhance lateral growth of InN by altering the surface species and increasing their ability to move on a surface even at the low temperatures dictated for InN. In detail CBrCl3 was co-injected during growth to form volatile halides that have proven successful in enhancing the final deposited film quality significantly. In Figure 1, we report the X-ray diffraction patterns obtained on different InN layers grown under increasing CBrCl3/TMIn ratios. Interference fringes, known as “Pendellosung fringes” are clearly observed as the injected CBrCl3 amount increases. This is proof of a high in-plane coherence, due to a spectacular improvement of the layer morphologies. Atomic force microscopy investigations were carried out to precisely quantify the surface rms roughness, and the results clearly demonstrate that the lateral growth is immensely improved by the use of CBrCl3 to form halides (see images in Figure 2, showing a strong decrease of the surface roughness, see z-scale). Another representation, demonstrating that surface roughness is drastically reduced, is given in the graph in Figure 2 where we plotted the distribution of surface features mean heights versus CBrCl3 content.

Figure 1 XRD results using CBrCl3

Combined with the use of low temperature buffer layer, this approach leads to a breakthrough in InN material quality. Roughness values are now such that device fabrication is possible and further work is ongoing to develop this exciting technology.

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Figure 2 Surface roughness data using CBrCl3

Related communications output from project: Int. Workshop on Nitride Semiconductors (IWN2008), Montreux, Switzerland, October 2008 ●

Halide mediated improvement of the lateral growth of InN in MOCVD O. Briot, S. Ruffenach, M. Moret, B. Gil, Ch. Giesen, M. Heuken, S. Rushworth, T. Leese and M. Succi

●

Growth and doping of InN films by MOVPE O. Briot, S. Ruffenach, M. Moret, B. Gil, Ch. Giesen, M. Heuken, S. Rushworth, T. Leese and M. Succi

2nd Int. Symposium on Growth of III-Nitride Semiconductors (ISGN2), Shuzenji, Japan, July 2008 ●

Growth of InN films and nanostructures by MOVPE O. Briot, S. Ruffenach, M. Moret, B. Gil, Ch. Giesen, M. Heuken, S. Rushworth, T. Leese and M. Succi

●

MOVPE growth of InN buffer layers on sapphire O. Briot, S. Ruffenach, M. Moret, B. Gil, Ch. Giesen, M. Heuken, S. Rushworth, T. Leese and M. Succi

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Alternative precursors for MOVPE growth of InN and GaN at low temperature S. Ruffenach, M. Moret, O. Briot, B. Gil, Ch. Giesen, M. Heuken, S. Rushworth, T. Leese and M. Succi

AWI Facility Details

cont’d from page 1

Frequent meetings and conference calls between the research group in Matsumoto and the research groups in the USA and the UK allow for recently achieved data to be discussed internally, commented upon and then made available to our customer base on an individual and confidential basis. Three ALD Reactors situated in a Class 1000 clean room are available to deposit thin films, layer by layer in a controlled sequence cycle using specially designed and fit for purpose chemical precursors. Close by is situated a Rapid Thermal Annealer (RTA) to stabilise the crystal structure of the thin film formed. Further microscopy equipment including a Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) is used to examine the surface of the film in extremely fine detail. Ellipsometry techniques are also available in-house to measure film thicknesses very accurately and an X-ray Diffractometer (XRD) is used to measure not only chemical composition of the film but also its crystallographic structure. Included in the characterisation tools available is also an Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES) which measures extremely accurately the qualitative and quantitative components of the material composition of the films deposited. 350

Ti Source Assessment

Thickness (Å)

300 250 200 150 100 50 0

0

100

200

300

400

Number of ALD cycles

500

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SAFC Hitech News

REACH Pre-registration Successfully Accomplished Sigma-Aldrich is proud to announce that the first hurdle of the REACH legislation process has been successfully completed by the pre-registering of several hundred chemical substances. On December 1st, 2008 at 24:00 GMT the official REACH pre-registration period ended. During the 6-month period prior to this date importers and manufacturers of chemicals or formulations in quantities >1000kg per year in the EU had the opportunity to pre-register their substances at the European Chemicals Agency (ECHA) to benefit from longer transition periods for final registration. According to the latest info from the ECHA more than 47,000 companies have made more than 2.2 million (!) pre-registrations for around 54,000 different substances - much higher than expected. Sigma-Aldrich pre-registered over 1000 entries for 10 different legal entities in Europe. This was only the first little step of a long ongoing and challenging process of REACH implementation, however, Sigma-Aldrich is committed to complying with the highest safety standards to assure customer confidence and provide comprehensive information for chemical handling and usage. Information for customers about REACH can be found on our website: http://www.sigmaaldrich.com/customer-service/reach.html

A Focus on Procurement in a Global Supply Chain Sigma-Aldrich collectively purchases about one billion dollars per year of materials and services and a key factor is ensuring the full value of the Company’s buying leverage to obtain the best quality items for the best price. Just as our customers wish to obtain the best deal for our products we must review our own supply chain. This involves both “direct” spend, the materials utilised in manufacturing end products sold to customers, as well as “indirect” spend - all other goods and services needed to do business. Historically we have performed well in this area but there is always room for improvement. A global review is currently ongoing to ensure the most efficient protocols are in place and the resulting benefits will be better connectivity with suppliers and an enhanced supply chain which can provide higher quality, time to delivery and value for money. IT solutions Sigma-Aldrich Global Supply Chain ®

Common Processes - Seamless Integration - Outstanding Service

will reduce paper usage in line with the corporate Green policy as well as speeding cycle time, provide facile tracking of the status of the requisition and purchase orders electronically including follow up with vendors directly. These outcomes will in turn lead to reduced cost and optimum value that can be passed on to our customers to maintain the high quality of service they require and demand.

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Tungsten Carbonitride Thin Films A long-standing collaboration between University College London (UK) and SAFC Hitech has seen recent advances in the field of coatings on glass. The principles behind these advances can be applied to a wide range of material systems and have applications in a number of electronic devices to increase speed and reduce feature size. Claire Carmalt's group at University College London, in collaboration with the SAFC Hitech research team in Bromborough, used chemical vapour deposition (CVD) to produce thin films of tungsten carbonitride (WNxCy) from new precursors. WNxCy can be used as an effective barrier layer to prevent Cu migration from circuit wires into semiconducting components and the application of CVD to apply coherent films over reduced areas significantly helps scaling efficiencies. The precursors investigated included a range of tungsten imido complexes to produce compounds with ideal thermal properties for CVD. Careful tuning of the ligands surrounding

Chemical vapour deposition produces hard thin films of tungsten carbonitride

the tungsten centre was performed to optimise these thermal properties to enhance the fabrication of tungsten carbonitride thin films in the parameter space necessary for devices. The decomposition mechanism studies and explanation of observed thermal events for each precursor was key in determining storage stability, transport properties and deposition temperature capabilities. A structured approach was followed to identify the highest potential molecules in the shortest timeframe and then to demonstrate their effective use in CVD. In practice four closely related precursors were established for growth trials and all yielded WNxCy thin films on glass using Low pressure CVD at 550°C. The actual molecules were: [W(µ-NtBu)(NtBu)Cl2(H2NtBu)]2, [W(NtBu)2Cl2(TMEDA)] (TMEDA = N,N,N',N'tetramethylethylenediamine), [W(NtBu)2Cl2(py)2] (py = pyridine) and [W(NtBu)2Cl(N{SiMe3}2)]. Grey mirror-like films were grown with a nitrogen or ammonia bleed gas and in all cases the chlorine content of the deposited films was less than 1 at%. Oxygen levels were decreased using ammonia and, surprisingly, this did not significantly

py t

BuN

t

Cl W

BuN

Cl

py

change the carbon content of the resulting films. The films were uniform, adhesive, abrasion resistant, conformal and hard, being resistant to scratching with a steel scalpel. X-ray powder diffraction patterns of all the films showed the formation of ß-WNxCy.

py = pyridine

As a comparison the team also investigated aerosol-assisted chemical vapour deposition (AA)CVD using one of the precursors [W(µ-NtBu)(NtBu)Cl2(H2NtBu)]2 and found the resulting layers to be amorphous tungsten carbonitride films. Further studies are ongoing to understand the differences seen between precursors and deposition techniques. Full results have been published (http://www.rsc.org/Publishing/Journals/DT/article.asp?doi=b808650h) For further information contact Claire Carmalt at [email protected]

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SAFC Hitech News

Improved Processes and Materials for Energy Saving Glazing Partners: SAFC Hitech, Liverpool University, Pilkington Roles: Precursor selection, Process demonstration, Process scale up To further expand the areas under investigation at SAFC Hitech, a study into coatings on glass was proposed. A partnership with Liverpool University and Pilkington was developed to focus the research direction and due to the highly relevant nature of this work funding support from the UK government has been granted. In detail a successful application was made to the Technology Steering Board (TSB) competition relating to Low Impact Building Innovation Platform and a three-year project (PROMISE) will run to develop new technologies to enhance glazing performance. Low emissivity glass is playing an increasing role in improving building energy efficiency with a key feature a thin coating with appropriate refractive index to capture solar energy and reduce heat loss. Alternative precursors and deposition technologies will be developed to enable next generation products to be brought to market for low impact buildings.

New Regulations for Certification of Containers The build of SAFC Hitech bubblers, ampoules and cylinders is to the highest of standards and certification of these containers must follow legislative regulations due to their classification as pressure vessels. This pressure rating demonstrates that the vessel is safe and the methods employed also ensure DOT certification is met in all cases. It is clearly important that the transport of hazardous chemicals is performed in the safest manner possible and that the strict road, sea and air regulations are adhered to. DOT certified containers are guaranteed to meet all specifications and are also a legal requirement for safe, trouble-free shipping of products both nationally and internationally. Each vessel is individually tested using robust protocols when it is fabricated and first placed into service. With the increasing requirement to re-use containers and extend their lifetime, the situation regarding retest of the bubblers has risen to a higher profile and recent new regulations relating to the pressure testing of ampoules have introduced a validity of 5 years for the certification. SAFC Hitech must therefore fully re-test every container by the 5th anniversary of its construction to maintain its pressure rating. The identification of bubblers globally that are at risk of having the pressure certificate expire is currently underway and customers will be notified of their containers’ status if the time limit is pressing. SAFC Hitech will offer a pressure re-test and certification service to ensure customer owned ampoules remain in a transportable state and issues of shipment blockage due to legislative and safety concerns are avoided. For further information of the impact of the impending new protocols please contact your local SAFC Hitech representative.

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Crystal Grade Metal Halides Make Big Impact SAFC Hitech proudly introduced its first line of products targeted for the radiation detection market, Crystal Grade Metal Halides, at the IEEE Nuclear Science Symposia-Medical Imaging Conference (NSS-MIC) that was held in Dresden, Germany Q4 2008. These products mark a new direction for SAFC Hitech as we continue to integrate our capabilities and resources and craft offers to new segments of the electronics market. The launch at the show was highly successful from the perspectives of sales performance and branding with many customers visiting our booth for information on the new product range. The crystal grade metal halides find applications as scintillation detectors in medical imaging, security detection and astrophysical equipment. Our high purity products, manufactured at the AAPL facility in Urbana Il in the US, include iodide salts of sodium, cesium and thallium with new halide salts of lanthanum, strontium and europium under development. To further support our customers’ efforts, we offer key services that ease processing, reduce waste disposal complexities and improve overall cost of ownership. First SAFC Hitech can provide blended halides for doped crystal growth with high accuracy and control to reduce handling necessities on site. Secondly we will accept return of unused or scrap Na, Cs or Tl materials for reprocessing to minimise hazardous waste disposal procedures and cost for the customer. In this exciting new area, new and existing SAFC Hitech customers have approached us for material supply and invitations to participate in joint development projects. For example, the new scintillator SrI2:Eu has gained significant interest due to its improved properties. In 2009 our goal is to continue to deliver an exemplary service to our customers. Furthermore, we aim to reinforce our manufacturing capabilities at Urbana through capital investment and to expand on our current offers to meet future market demands.

Geoff Irvine Expanded Role We are pleased to announce the promotion of Geoff Irvine to VP Business Development for SAFC Hitech. In his new role he will have responsibility for new business development through organic growth and acquisition, and marketing for Hitech as well as responsibility for AAPL, the Aldrich-APL Joint Venture, where he serves as President. Geoff joined Sigma-Aldrich Corporation in 2001 with responsibility for identifying and capitalising on marketing opportunities to grow the organometallics product line revenue. Geoff’s responsibilities quickly broadened to include new product development and overall product line strategy. In early 2003, Geoff moved to the SAFC business unit segment that would subsequently become SAFC Hitech and indeed was instrumental in the acquisition of the Epichem Group in 2007 and the subsequent integration with the traditional Hitech business to make a powerful force in the electronics industry.

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SAFC Hitech News

Cadmium Oxide as an Alternative TCO Transparent conducting oxides (TCOs) have found use in a broad array of applications including photovoltaic (PV) cells, flat panel displays, and light emitting diodes. The dominant material system currently is indium tin oxide (ITO), however, alternatives are being sought due to the price and availability of In. Face-centred cubic cadmium oxide has a relatively low intrinsic band gap of 2.28 eV, while its low effective carrier mass allows for heavily doped samples which can have band gaps as high as 3.35 eV. Sn-doped CdO has been shown to allow access to mobilities of 607 cm2 V-1 s-1 [1] making it suitable for a large number of TCO applications. CVD is particularly attractive for TCO synthesis because of its use in conformal, large volume, thin film manufacturing processes. A key prerequisite for CVD is a volatile precursor and at present only a limited number of examples are available. Historically, CdO films have been grown via CVD using the combination of dimethylcadmium as a precursor and butanol as an oxygen source [2]. This dual-source approach leads, naturally, to speculation as to the likelihood of organocadmium alkoxides as intermediates in this process, and thus such species would be potential single-source precursors (SSP) in their own right. Indeed, work on the analogous ZnO process identified MeZn(OiPr) as just such an SSP. [3] The focus of interest at Bath has been to exploit donor-functionalised alkoxides and so exploration of a series of reactions between Me2Cd and the requisite alcohol have been performed, and the resulting materials assessed for use as CVD precursors. In detail the compounds studied involved the ligands in Figure 1.

NMe2 Me2N

Me2N OH I: Hdmae

NMe2

Me2N

NMe2

OH

OH

II: Hbdmap

III: Htdmap

Figure 1 Functionalised alcohols employed to react with Me2Cd to form MeCd(L) compounds

Characterisation of each of the resulting compounds (MeCd(L)) highlighted the dimeric nature of the highest potential CVD source, [MeCd(tdmap)]2, (see Figure 2) and this material was studied in a simple hot wall low pressure chemical vapour deposition (LPCVD) reactor which has been described in detail elsewhere.[4] Films were deposited on 76 × 26 × 1.0 mm microscope slides. A 0.15 g quantity of [MeCd(tdmap)]2 was heated to 140 °C in a tube furnace under a vacuum of about 0.1 mmHg; the glass substrate was also heated to 140 °C and the run time was 30 min.

Figure 2 Crystal structure of [MeCd(tdmap)]2 highlighting CdOCdO central ring

Page 11

Thermal treatment of the source showed some decomposition at T > 100 °C with complete decomposition by 300 °C leaving a mass corresponding to CdO and indeed in the LPCVD trials at 140 °C smooth, pale yellow films of approximately 300 nm thickness were formed, which energy-dispersive X-ray spectroscopy (EDXS) clearly showed contained cadmium and oxygen (Figure 3). The XRD of these films (Figure 4) shows crystallinity despite the low deposition temperature and the peaks can be indexed to cubic CdO highlighting the nature of the film as that targeted. Interestingly, no carbon was observed in the final film which suggests a clean decomposition pathway that is accentuated under vacuum conditions. No ancillary oxygen source was used, making this the first true example of CdO deposition from an SSP. Further work has also been performed using the ZnO analogues and also CVD trials on mixed ZnO/CdO systems undertaken. Full details of

Figure 3 EDXS of LPCVD film highlighting Cd and O content (C, Au peaks are due to the sample preparation, Si results from the exposed glass substrate)

the results are published [5] and highlight the great promise of these new precursor families for low temperature TCO deposition. References [1] Yan, M. L. M.; Kannewurf, C. R.; Chang, R. P. H. Appl. Phys. Lett. 2001, 78, 234 [2] Irvine, S. J. C.; Ellis, D. M. J. Mater. Sci. 2004, 15, 369 [3] Auld, J., Houlton, D. J., Jones, A.C., Rushworth, S.A., Malik, M. A., O'Brien, P., Critchlow, G.W., J. Mater. Chem., 1994, 4(8), 1249-1253 [4] Horley, G. A.; Mahon, M. F.; Molloy, K. C.; Haycock, P. W.; Myers, C. P., Inorg. Chem. 2002, 41, 5052–5058. [5] Johnson, A. L., Hollingsworth, N., Kociok-Kohn, G., Molloy, K. C., Inorg. Chem. 2008, 47, 9706-9715

Figure 4 XRD of the as deposited film. The film is indexed to cubic cadmium oxide (PDF 75-1529)

The work reported was performed by postgraduate student Nathan Hollingsworth with the support of SAFC Hitech in the group of Dr A Johnson and Prof KC Molloy.

Conference Representation for 2009 SAFC Hitech personnel will again be at all the key semiconductor conferences and workshops around the world to network with customers and the scientific community. We are dedicated to providing state-of-the-art chemicals and services across a wide spectrum of application areas and deposition technologies to offer a competitive advantage for the end user. To convey the full range of our products, both standard and developmental, our expert representatives will be pleased to meet you at one of a multitude of forthcoming events, so please look out for our booth and come along for a chat about sales enquiries, technical support or just the weather back home. Details of events that SAFC Hitech will be attending during the year are detailed on our website www.safchitech.com and it is updated regularly to be sure the latest information is available to our customers

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SAFC Hitech News

SAFC Hitech International Sites Global email: [email protected] United Kingdom SAFC Hitech, Power Road, Bromborough, Wirral, CH62 3QF Tel: +44 (0) 151 334 2774 Fax: +44 (0) 151 334 6422 United States SAFC Hitech, 1429 Hilldale Ave, Haverhill, Massachusetts, 01832-1300, USA Tel: 610 706 0606 Fax: 610 706 0888 Japan Daido Air Products Electronics Inc, 6-17-17, Shinbashi, Minato-Ku, Tokyo, 105 0004 Japan Tel: +81 3 3432 7032 Fax: +81 3 3578 7827 China SAFC Hitech, Block 8, Room 803, Mandarine City, HongXu Road, No 788, Shanghai, China, 201103 Tel: +86 21 6446 1686 Fax: +86 21 6405 4343 Korea Doje Corporation, 211-2 SongJeong-Dong, GwangJu, GyungGi-do 464-903 Korea Tel: +82 31 764 4907 Fax: +82 31 764 4961 Singapore DNIV, 10 Ang Mo Kio Street 65, #03-04, TECHPOINT, 569059, Singapore Tel: +65 6 483 3386 Fax: +65 6 483 2698 Taiwan SAFC Hitech, 10F No.28 Sec 3, Nan King East Road, Taipei 104, Taiwan Tel: +88 62 2509 1399 Fax: +88 62 2501 6279 Europe Fab Support AB, Dovregatan 18, SE-164 36 Kista, Sweden Tel: +46 (0) 8 5620 3330 Fax: +46 (0) 8 5716 2850

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