| 摘要 |
PROBLEM TO BE SOLVED: To obtain an MOS transistor in which diffusion of source-drain is suppressed. SOLUTION: The process flow for fabricating an MOSFET having an LDD (110 13) is altered using a combination 7 of arsenic and phosphor for adapting the side face profile to satisfy both the series resistance and the channel hot cariier requirements. The series resistance is controlled by a relatively large quantity of arsenic and the side face junction profile is determined by a,smaller quantity of phosphor. Consequently, an intermediate profile can be achieved. A relatively large quantity of arsenic is implanted at the time of forming the LDD (11, 13). Extension of the side face of LDD (11, 13) is altered to satisfy the hot carrier lifetime by decreasing the quantity of arsenic to be implanted and it is set lower than 1×10<14> cm<-2> , preferably at 6×10<13> cm<-2> .
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