ECE 440 Homework XIV Fall 2005 Due: Wednesday, November 16, 2005 1. For an ideal MOS structure, the SiO 2 thickness is 150 Å, and the substrate is doped with 10 16 /cm 3 acceptors. Determine the threshold voltage, V T , required to achieve strong inversion and find the electric field in the oxide when the applied bias V=V T . Repeat for a different MOS where the SiO 2 thickness is 40 Å but the substrate doping is the same. 2. Other than aluminum, polysilicon is another common gate metal for the MOS structure in silicon. By incorporating heavy doping during chemical vapor deposition of polysilicon one can greatly increase the conductivity of the polysilicon “metal”. Accidentally our engineer has made a mistake and heavily doped the polysilicon to be p-type. Reconstruct a diagram similar to Figure 6-17 showing the variation of the metal-semiconductor work function
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