Method for determining the hot carrier lifetime of a transistor

Abstract

The present invention provides a method for determining a hot carrier lifetime of a transistor. In one embodiment, the method comprises the steps of determining an initial transconductance (g,) of a transistor, and then, applying a stress voltage, which does not exceed a maximum breakdown voltage of the transistor, to the transistor to cause a transconductance degradation of the transistor, and then determining a subsequent transconductance (g,) of the transistor. A hot carrier lifetime of the transistor can then be determined as a function of g,and g,. Thus, the present invention provides a method in which the hot carrier lifetime is determined from sequential transconductance measurements without intervening, transistor characteristic tests that are typically conducted between the transconductance measurements that degrade the sensitivity of the g,measurement. The present invention provides a method that allows for an accurate determination of the hot carrier lifetime within a very short period of time, and therefore, can be used to monitor the hot carrier lifetime quality of the devices as they are fabricated without substantial increases in production downtime typically required to make hot carrier lifetime measurements.