High-energy ion irradiation effects on thin oxide p-channel MOSFETs

P-channel MOSFETs of a commercial 0.25 /spl mu/m CMOS technology have been irradiated by high linear energy transfer (LET) iodine (I) and low LET silicon (Si) ions up to 300 Mrad(Si) and 500 Mrad(Si), respectively. Threshold voltage variations (/spl Delta/V/sub TH/) up to -0.46 V and -0.44 V have been measured at the highest I and Si doses. Both oxide positive trapped charge (/spl Delta/V/sub OX/) and interface states (/spl Delta/V/sub IT/) contribute to /spl Delta/V/sub TH/ with a ratio /spl Delta/V/sub IT///spl Delta/V/sub OX/ /spl ap/ 1 (1.6 V (> 3.4 V).