NEW RELIABILITY ISSUES OF CMOS TRANSISTORS WITH 1.3 nm THICK GATE OXIDE

摘要

Several new reliability issues facing CMOS transistors with t_(ox)=1.3 nm thick gate oxide and their impacts on projection of operation voltage V_(10Y) for 10-year lifetime are discussed: 1). Oxide lifetime is defined by an event taking place much earlier than oxide breakdown: a strongly transistor-size dependent increment in gate leakage current. Contrary to T_(BD), the newly defined oxide lifetime is shorter when the transistor size is smaller. 2). Contrary to previous reports on thicker gate oxide, V_g=V_d is the worst-case hot carrier degradation condition for both n-MOS and p-MOS, with p-MOS showing smaller V_(10Y) than n-MOS. 3). A "dynamic" NBTI of p MOS devices during AC stressing is reported. It is clearly demonstrated that the conventional (static) NBTI underestimates p-MOS device lifetime. The DNBTI determines the overall CMOS device lifetime and will have significant impact on projection of maximum operating voltage in practical operation of digital circuits.