Title :
Long-term effects of sidegating on GaAs MESFETs
Author :
Cholan, Hema ; Stunkard, Douglas ; Rubalcava, Tony
Author_Institution :
TriQuint Semiconductor Inc., Beaverton, OR, USA
fDate :
March 31 1992-April 2 1992
Abstract :
The main purpose of this study was to monitor the effects of sidegating over time. Both enhancement mode and depletion mode MESFETs, with and without isolation implants, were tested at elevated temperatures. The sidegate effect is caused when carriers are introduced into the substrate with a negative potential contact. All electrodes were manufactured with ohmic contacts. Once in the substrate, the electrons move towards more positive potentials. As they move through the GaAs substrate, some electrons are trapped. If trapped near the FET, the electrons can influence the threshold or pinchoff voltage of the device. In this study, the influence was measured by monitoring the channel current in MESFETs. A FET was considered sidegated, when the channel current was reduced by 10%. This study was performed also to investigate whether the wearout failure mechanisms make MESFETs more susceptible to sidegating effects as they age.<>
Keywords :
III-V semiconductors; Schottky gate field effect transistors; electron traps; failure analysis; gallium arsenide; semiconductor device testing; GaAs; GaAs substrate; channel current; depletion mode MESFETs; electron trapping; enhancement mode MESFET; isolation implants; long term effects; negative potential contact; ohmic contacts; pinchoff voltage; sidegating; threshold voltage; wearout failure mechanisms; Electrodes; Electron traps; FETs; Gallium arsenide; Implants; MESFETs; Manufacturing; Monitoring; Temperature; Testing;
Conference_Titel :
Reliability Physics Symposium 1992. 30th Annual Proceedings., International
Conference_Location :
San Diego, CA, USA
Print_ISBN :
0-7803-0473-X
DOI :
10.1109/RELPHY.1992.187621
