Lecture 16 Active Microwave Diodes

1. Transferred Electron Devices (TEDs)

• Gunn-Effect Diodes (GaAs Diods)

• InP Diodes

2. Avalanche Transit-Time Devices

• Read Diode

• IMPATT Diodes

• (BARITT Diodes)

Fundamental Different from FETs

• Bulk devices having no junctions or gates

• Compound semiconductors (GaAs or InP)

• TEDs operate with “hot” electrons whose energy is very much greater than the thermal energy.

• Ridley and Watkins proposed in 1961• Hilsum calculated the transferred electron effect in III-V in 1962; experiment fails.• J.B. Gunn of IBM discovered the so-called Gunn effect in 1963 and rejected the above theory.• Kroemer explained the origin of the negative differential mobility is

Ridley-Watkins-Hilsum’s mechanism

Magic Number : 3000V/cmMagic Number : 3000V/cm

Two-valley model theory

Homework:

High-field Domain Formation:High-field Domain Formation:

n+-p-i-p+

Read in 1958 (theory)Lee et al. 1965 (demonstration)

τ=L/vd

Homework:Read “Modern Semiconductor Device Physics” by SzeChapter 6 pp. 343-401

Scanned pdf file could be provided upon requests.

Due on November 30, 2010 (Tuesday)