Lithography CD Variation effects on LFNDMOS Transistor Hot-Carrier Degradation

Abstract

Developing reliable high voltage transistors requires consistent manufacturing of critical architectural parameters within the device over time and with various design configurations. Structural parameters that directly affect reliability are especially crucial to delivering robust parts to the market place. In this paper it is shown that the nwell and pwell photo critical dimension (CD)'s for a 25 V lateral field n-type transistor (LFNDMOS), are significant control parameters for minimizing hot-carrier degradation and thus, improving the reliability. Variations in manufacturing photo CD's, such as, the edge proximity of the nwell (used as the extended drain) and the pwell (used as the body) to the bird's beak (BB) was found to directly effect interface trap formation and hot-carrier degradation. By understanding these critical structural parameters a more reliable manufacturing process can be developed