ece340Spring04HW15sol - ECE 340 Homework XV Due Friday...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
ECE 340 Homework XV Spring 2004 Due: Friday, April 23, 2004 1. Aluminum and polysilicon are commonly used as gate metals for the MOS structure in silicon. Assume that platinum is used as the gate metal. Reconstruct a diagram similar to Figure 6-17 showing the variation of the metal-semiconductor work function potential difference Φ ms with substrate doping concentration. The work function of Pt is 5.7 V and the electron affinity of silicon is 4.0 V. Show your work and draw to scale with accuracy. Solutions: For n-type silicon: ln 5.7 4.0 0.55 0.0259ln 1.15 0.0259ln 2 g dd ms m s m si ii i E NN kT n qn n n χ ⎛⎞ Φ= Φ− + − = − + = + ⎜⎟ ⎝⎠ For p-type silicon: ln 5.7 4.0 0.55 0.0259ln 1.15 0.0259ln 2 g aa ms m s m si i E kT p n n + + + + = Plots based on these two equations: 2. (a) Find the voltage V FB required to reduce to zero the negative charge induced at the semiconductor surface by a sheet of positive charge Q ox located x’ below the metal. (b) In the case of an arbitrary distribution of charge ρ
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Page1 / 4

ece340Spring04HW15sol - ECE 340 Homework XV Due Friday...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online