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Unformatted text preview: at the conduction band edge, so the electron affinity is also 4.01 eV, whereas for p+ polysilicon, the Fermi energy is at the valence band edge so that the electron affinity is 4.01+1.12=5.13 eV. In addition, we need to have ⎛ 6 × 1015 ⎞ ϕ fp = EFi − EF = 0.0259 ln ⎜
= 0.33eV ⎝ 1.5 × 1010 ⎟
⎠ The required quantity is E
⎛
⎞
φms = φm − ⎜ χ + G + ϕ fp ⎟ . ⎝
⎠
2 (a)  0.62 eV (b)  0.89 eV (c)  0.23 eV . 10.16 An n+ polysilicon gate—silicon dioxide—silicon MOS capacitor has an oxide thickness of tox = 18 nm, and a doping of Na = 1015 cm 3. The oxide charge density is Q’ss = 6 X 1010 cm 2. Calculate the (a) flat band voltage and (b) the threshold voltage. (a) To begin, we need to calculate the φms and the oxide capacitance (per u...
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This document was uploaded on 02/19/2014.
 Fall '14

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