A real-time C-V measurement circuit for MOS capacitors under current stressing

A real-time C-V measurement circuit for MOS capacitors which are under constant current stress is presented. For this system, the MOS device is kept current-stressed and its stressed C-V characteristics can be measured instantaneously when desired. The charge filling information on oxide traps and surface states can be obtained in real time during the stressing process, even to the point of capacitor breakdown. With this circuit it has been shown that, for an Al-gate MOS structure, charges on traps and interface surface states recover immediately after the stressing is removed. It is demonstrated that the breakdown of the oxide is a sudden phenomenon, and is caused mainly by charge trapping in the oxide.<
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