Title :
Measurement of substrate current in SOI MOSFETs
Author :
Nguyen, Cuong T. ; Ver Ploeg, Eric P. ; Kuehne, Stephen C. ; Plummer, James D. ; Wong, S. Simon ; Renteln, Peter
Author_Institution :
E&EE Dept., Univ. of Sci. & Technol., Kowloon, Hong Kong
fDate :
4/1/1994 12:00:00 AM
Abstract :
A new "Quasi-SOI" MOSFET structure is shown to allow direct measurement of substrate current in a fully-depleted SOI device. The holes generated by impact ionization near the drain are collected at the substrate terminal after they have traversed the source-body barrier and caused bipolar multiplication. By monitoring this hole current, direct characterization of the impact-ionization multiplication factor, M, and the parasitic bipolar gain, /spl beta/, was performed. It was found that M/spl minus/1 increases exponentially with V/sub DS/ and decreases with V/sub GS/, exhibiting a drain field dependence. The bipolar gain /spl beta/ was found to be as high as 1000 for V/sub GS//spl minus/V/sub T/=0 V and V/sub DS/=/spl minus/2.5 V, but decreases exponentially as V/sub DS/ increases. Finally, it was found that /spl beta/ also decreases as V/sub GS/ increases.<>
Keywords :
carrier mobility; electric current measurement; impact ionisation; insulated gate field effect transistors; semiconductor device testing; semiconductor-insulator boundaries; silicon; SOI MOSFETs; bipolar multiplication; drain field dependence; fully-depleted SOI device; hole current; impact ionization; multiplication factor; parasitic bipolar gain; quasi-SOI MOSFET structure; source-body barrier; substrate current; Bipolar transistors; Charge carrier processes; Current measurement; Electric breakdown; Electrons; Impact ionization; MOSFET circuits; Monitoring; Performance gain; Substrates;
Journal_Title :
Electron Device Letters, IEEE
