# hw16 - 2/V-s and Z=10L For the device n polysilicon is used...

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ECE 440 Homework XVI Spring 2006 Due: Monday, April 24, 2006 1. For an n-channel Si MOSFET with an oxide thickness d=100 Å, a channel mobility μ n = 1000 cm 2 /V-s, Z=100 μm, and L=5 μm, determine the threshold voltages for N a = 2x10 15 and 2x10 17 /cm 3 , respectively. Calculate and tabulate I D (V D ,V G ) in the linear region at 300 K. Allow V D to take on values of 0.1, 0.3, 0.5, 0.7, 0.9 and 1.1 V for V G =2, 3, 4, and 5 V. Assume that Q i = 2x10 11 qC/cm 2 and n + polysilicon is used as the gate metal. Also, determine I D sat in the saturation region for each gate bias and doping. 2. Plot I D vs. V D for V G = -2, -3, and -4V for a thin-oxide (100Å) p-channel transistor. The substrate doping and effective interface charge are N d =10 16 cm 3 and Q i = 5x10 10 q C/cm 2 , respectively. Assume that I D sat remains constant beyond pinch-off and μ p =200 cm
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Unformatted text preview: 2 /V-s and Z=10L. For the device, n + polysilicon is used as the gate metal. 3. Refer to the n-channel MOSFET in problem 1 whose N a = 10 17 /cm 3 . What is V T if the gate oxide thickness is reduced to 30Å? At this thickness, unfortunately, the leakage current through the gate begins to rise appreciably due to tunneling. To suppress the leakage current a thicker gate insulator is needed. In order to keep the threshold voltage the same, a different gate insulator having a larger dielectric constant, for example silicon nitride is required. Assuming all other parameters are kept the same, determine the nitride thickness that would give rise to the same V T as that in silicon dioxide. The dielectric constant of silicon nitride is about 7.0....
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## This note was uploaded on 12/01/2011 for the course ECE 340 taught by Professor Leburton during the Spring '11 term at University of Illinois, Urbana Champaign.

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