HW2 Solutions.pdf - EEE 436\/591 Fall 2016 Homework 2 Due Sep 27th Total points 40 10 bonus points 1(Total 10 pts Phosphor is diffused into Si from a

# HW2 Solutions.pdf - EEE 436/591 Fall 2016 Homework 2 Due...

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EEE 436/591 Fall 2016 Homework 2 Due: Sep. 27 th Total points: 40 + 10 bonus points. 1.(Total: 10 pts) Phosphor is diffused into Si from a limited surface concentration so that Gaussian diffusion dominates. The doping density profile is given by (x=0 at wafer surface) DtxDttxND4exp10),(215where D= 1.05x10-15cm2/s. For an p-type substrate doped to NA= 2x1015cm(a) (3 pts) Calculate and plot ND(x,t) versus x(in cm) for t= 60 min (softwares, such as matlab, excel, etc. are required to be used to generate the plot) (b) (2 pts) Determine the junction depth xj(in cm) (junction depth xjoccurs at NA= (c) (total: 5 pts) Assuming the depletion region extends from x1to x2(x1<xj< x2) for this PN junction in equilibrium and the depletion approximation is valid, can you sketch the charge distribution in the depletion region (2 pts) and the corresponding electric field distribution pts), qualitatively. Can you also explain which side (p or n) would host a longer depletion region, i.e., which is larger,xj-x1or x2-xj? (1 pts) -3 N D ) (2 ) j ρ 2