Patent ID: 8283941
Filing Date: 2012-10-09
Classification: G01R,H01L

Abstract:
1. An alternating current (AC) stress test circuit for hot carrier injection (HCI) degradation evaluation in semiconductor devices, comprising: a ring oscillator circuit having a plurality of stages electrically connected in series between an input terminal and an output terminal electrically connected with the input terminal and whereby forming a loop, wherein each of the stages comprises a first node and a second node, a designated one of the stages serves as device under test (DUT); a first isolating switch and a second isolating switch, respectively electrically connecting the first node and the second node of the DUT; an input means being electrically connected to the first isolating switch and for applying a gate on voltage to the first node through the first isolating switch to bias the DUT; and an output means being electrically connected to the second isolating switch and for measuring a current flowing from the second node through the second isolating switch.