Improved transconductance under high normal field MOSFETs with ultrathin nitrided oxides

The gate-voltage dependence of electron mobility at 298 and 82 K in MOSFETs with nanometer-range thin (reoxidized) nitrided oxides prepared by rapid thermal processing (RTP) at 900-1150 degrees C for 15-300 s is discussed. Rapid nitridation improves the mobility and current derivability under high normal field over thermally grown oxides at both temperatures: the transconductance g/sub m/ at a gate drive of 3.5 V is improved by half an order of magnitude, whereas the peak g/sub m/ remains comparable to that of an oxide. Nitridation also avoids the negative g/sub m/ observed at 82 K for an oxide MOSFET. These improvements are substantially unchanged by additional reoxidations.<
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