Plasma-Induced Transconductance Degradation of nMOSFET with Thin Gate Oxide

Koji ERIGUCHI  Masatoshi ARAI  Yukiharu URAOKA  Masafumi KUBOTA  

IEICE TRANSACTIONS on Electronics   Vol.E78-C    No.3    pp.261-266
Publication Date: 1995/03/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Sub-1/4 Micron Device and Process Technologies)
MOSFET,  transconductance,  Si-SiO2 interface state,  charge-to-breakdown,  antenna effect,  

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Degradation of metal-oxide-semiconductor field-effect transistors (MOSFETs) reliability such as the relative transconductance reduction by plasma exposure is evaluated. The linear region peak transconductance (gm) decreases with antenna ratio (exposed antenna area/gate area) due to the plasma-induced Si-SiO2 interface state generation. The Si-SiO2 interface-related gm reduction which is defined as (gm0gm)/gm, where gm0 is the initial value of gm, decreases as the gate oxide thickness decreases. It is also found that the decreasing amount of gm depends on the conduction current from the plasma. The correlation between the (gm0gm)/gm and the plasma-induced reduction of charge-to-breakdown of the gate oxide with a constant current stress (ΔQBD) is observed, and the result shows that the gm reduction of nMOSFET during the plasma process is severe to the plasma-induced damage compared with the gate oxide breakdown.