{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

HW-230B-2_2010a

# HW-230B-2_2010a - ECE 230B HW-2 Winter 2010 Solutions 1...

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

ECE 230B, HW-2, Winter 2010 Solutions 1. When the gate voltage greatly exceeds the threshold for strong inversion, a first-order solution of ψ s ( V g ) can be obtained from the coupled equations, Eqs. (2.195) and (2.182), by keeping only the inversion charge term. Show that ψ ψ ψ ε s B ox g fb B si a kT q C V V kTN + - - 2 2 2 2 ln ( ) under these circumstances. Estimate how much ψ s can be higher than 2 ψ B by substituting some typical values in the logarithmic expression. Solution: By keeping only the dominant inversion charge term in Eq. (2.182) and substituting it in Eq. (2.195), one obtains V V kTN C n N e g fb s si a ox i a q kT s = + + ψ ε ψ 2 2 / . When V g increases beyond the point where ψ s = 2 ψ B , most of that increase appears as inversion charge in the third term. There is very little change in the band bending beyond ψ s = 2 ψ B . A good approximate solution for ψ s is then obtained by letting ψ s = 2 ψ B for the second term and solving ψ s from the third term: ψ ψ ψ ε s B ox g

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

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 5

HW-230B-2_2010a - ECE 230B HW-2 Winter 2010 Solutions 1...

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

View Full Document
Ask a homework question - tutors are online