Reliability of in-situ rapid thermal gate dielectrics in deep submicrometer MOSFET´s

Several in-situ, rapid thermal gate dielectrics, 6.5-nm thick, including RTO, RTCVD, and RPECVD were used to fabricate fully implanted 0.25-μm NMOSFET´s along with Furnace gate oxides. The device reliability was studied by both channel hot-carrier stress and Fowler-Nordheim electron injection. It was found that devices having RTO or RTCVD oxides have about the same hot-carrier resistance as Furnace ones, while RPECVD oxides, deposited directly on Si without a grown oxide interface, were more susceptible to shifts. Both RTCVD and RPECVD oxides have a lower Si-SiO₂ barrier height (2.7 eV); nevertheless, RTCVD oxides show enhanced resistance against interface-state generation, threshold voltage shifts, and charging during Fowler-Nordheim stressing