The impact of NMOSFET hot-carrier degradation on CMOS analog subcircuit performance

This study presents some of the first experimental data on the impact of NMOSFET hot-carrier-induced degradation on CMOS analog subcircuit performance. Because of circuit design requirements, most NMOSFET's used for analog applications are biased in the saturation region with a low gate-to-source voltage. Under such operating conditions, in addition to interface states, significant numbers of hole traps are also generated inside the gate oxide. Because acceptor-type interface states are mostly unoccupied in the saturation region, hole traps are found to have a much more significant impact on analog NMOSFET device performance. The hot-carrier-induced degradation of analog subcircuit performance is also found to be quite sensitive to the particular circuit design and operating conditions. Circuit performance and reliability tradeoffs are examined.>