Open AccessRF/microwave non-destructive measurements of electrical properties of semiconductor wafers for thermophotovoltaic applications
Author(s) -
S Saroop,
J M Borrego,
R.J. Gutmann
Publication year - 1997
Language(s) - English
Resource type - Reports
DOI - 10.2172/319869
Subject(s) - thermophotovoltaic , materials science , optoelectronics , microwave , wafer , semiconductor , laser , diode , radio frequency , sheet resistance , optics , common emitter , electrical engineering , nanotechnology , physics , layer (electronics) , quantum mechanics , engineering
A radio-frequency/microwave measurement system has been designed for non-contacting determination of sheet resistance and excess carrier lifetime of low-bandgap materials and junctions, specifically GaSb-based alloys for thermophotovoltaic (TPV) applications. The design incorporates RF circuitry in the 100--500 MHz frequency range and utilizes a Q-switched YAG laser at 1.32 microns to photo-generate electron-hole pairs and conductivity modulate the material and/or junction under test. Supplementary measurements with a GaAs pulsed diode laser at 904 nm provides a faster transient response with near-surface photogeneration. Initial measurements on GaSb substrates, Zn-diffused materials and epitaxially grown layers are presented and discussed