Integrated Electronics(1)

TUTORIAL-2

Q1: Boron is implanted into n-type silicon at 300k ey with a ion dose of 4.5*10^13 ion/cm^2.Assume a gaussion distribution with Rp=0.735µm and ∆Rp=0.115µm. Calculate (a) the peak concentration (b) average resistivity (c) sheet resistance of implanted layer. assume µ(p)=200 cm^2/V

Q2: There are five different ways in which a BJT may be connected to obtain a monolithic pn-juction diode consider a npn transistor with I(EO)=1*10^ (-12) A ,I(co)=1.5*10^(-12) A. αn=0.98 at 300k .if a forward current of 5mA is required to flow through the diode .Deterime the diode voltage required for configuration and the configuration with the lowest forward voltage .

Q3: A 25.4µm thick silicon wafer has been doped uniformly with 5*10^16 atoms/cm^2 of boron and 1*10^7 atoms /cm^2 of phosphorous .Assuming µ(n)=3µp=1300 cm^2/vs Determine the sheet resistance of this layer.

Q4:The shift resistance of a boron diffused Si layer is 150Ω ,and its junction depth is 4 µm.Determine the average resistivity of the layer & the total number of boron atoms/cm^2. Assume µ(p)=250 cm^2/Vs. a 3 KΩ resistor is to be fabricated using their diffused layer with a width W=25µm.Determine the sheet ratio and the length of the resistor & design the resistor so as to maintain nearly a square shape.

Q5: A thin film capacitor has a capacitance of 7.2*10^-16 f/(µm)^2. The thickness of Si02 layer is 500 Å.Calculate the relative permittivity of Si02 layer.

Q6: A MOS capacitor is fabricated with a 400Å thick Si02 layer which has εr=3.5. How much chip area is required to obtain a capacitance 200 pf.