Method for automatic measurement of failure in subthreshold region of metal-oxide-semiconductor transistor

摘要

A method for detecting an abnormal condition of a MOS transistor in a subthreshold region. The method includes measuring a variation in a drain current with respect to a variation of a gate voltage of the MOS transistor to obtain a characteristics curve, and calculating, with reference to the obtained characteristics curve, a variation of transconductance with respect to each of the gate voltages to obtain a transconductance variable curve. The transconductance variable curve is differentiated. A number of inflection points in a curve obtained by the differentiation is determined to indicate the abnormal condition of the MOS transistor.