Title :
The reduction of backgating in GaAs MESFETs by impact ionization
Author :
George, Peter ; Hui, Kelvin ; Ko, Ping K. ; Hu, Chenming
Author_Institution :
Hewlett-Packard Co., Santa Clara, CA, USA
Abstract :
The reduction of drain current due to reverse substrate bias in GaAs MESFETs fabricated on EL2-compensated substrates is recovered with the application of sufficient drain bias. The recovery is shown to be due to the compensation of the negative space charge at the channel-substrate interface by holes generated by impact ionization in the MESFET channel. Illumination raises the value of drain bias needed for current recovery due to the requirement of additional hole flux to offset the effects of optically generated electrons on EL2 occupancy. Simulation results show that the channel current becomes independent of substrate bias when the bias value is sufficient to completely delete the p-type surface layer.<>
Keywords :
III-V semiconductors; Schottky gate field effect transistors; gallium arsenide; impact ionisation; EL2-compensated substrates; GaAs; MESFETs; backgating; channel current; channel-substrate interface; drain current; hole flux; impact ionization; negative space charge; p-type surface layer; reverse substrate bias; sufficient drain bias; Current measurement; Electron traps; Gallium arsenide; Impact ionization; Leakage current; Lighting; MESFETs; Schottky diodes; Semiconductor device modeling; Voltage;
Journal_Title :
Electron Device Letters, IEEE
