23.HJFET - 1 Heterojunction FETs MESFET What are these interfaces Why bother with HJFETs HEMT MODFET HJFET Why 3 names 2 Schottky barrier band

Info iconThis preview shows pages 1–10. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Heterojunction Heterojunction FETs FETs MESFET HEMT MODFET HJFET Why bother with HJFETs? What are these interfaces? Why 3 names?
Background image of page 1

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

View Full DocumentRight Arrow Icon
2 Schottky Schottky barrier band diagram barrier band diagram
Background image of page 2
3 Schottky Schottky barrier under bias barrier under bias Negative potential on n-type semiconductor NOTE: discontinuity in E F
Background image of page 3

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

View Full DocumentRight Arrow Icon
4 Forward bias in SB Forward bias in SB - - and PN and PN - - diodes diodes 2. What is the driving force here? 1. What is the bottleneck here? Φ B -qV a
Background image of page 4
5 Two Two heterojunctions heterojunctions in a HEMT in a HEMT y 2-DEG in the potential "well" AlGaAs/GaAs HJ Metal/AlGaAs HJ Note the doping
Background image of page 5

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

View Full DocumentRight Arrow Icon
6 Partial energy band diagram for HEMT Partial energy band diagram for HEMT E 0 χ E C E F E V i-GaAs n + -AlGaAs x Joined components Separated components
Background image of page 6
7 Simplifying the quantum well Simplifying the quantum well E y a • Triangular to finite square • Finite to infinite square •SWE±becomes : •wavenumberis •bc ’s :
Background image of page 7

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

View Full DocumentRight Arrow Icon
8 Energy is quantized Energy is quantized Energy Wavefunction Probability density E 1/m* 10X Si vs. GaAs
Background image of page 8
9 For a finite well For a finite well Wavefunction not completely confined Use undoped spacer
Background image of page 9

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

View Full DocumentRight Arrow Icon
Image of page 10
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 11/10/2010 for the course EECE 480 taught by Professor David during the Fall '09 term at The University of British Columbia.

Page1 / 17

23.HJFET - 1 Heterojunction FETs MESFET What are these interfaces Why bother with HJFETs HEMT MODFET HJFET Why 3 names 2 Schottky barrier band

This preview shows document pages 1 - 10. Sign up to view the full document.

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