基于POF的温度应力加速试验失效机理一致性研究

Failure Mechanism Consistency of Accelerated Test for POF Based Temperature Stress

目的通过失效物理手段得到温度加速寿命试验的失效机理突变点,节省试验样本,并为加速寿命试验的有效性提供保障。方法利用电子产品典型失效物理模型,在求解MOSFET器件激活能的基础上确定失效机理突变点,并开展失效物理分析,从微观分析的角度验证失效机理一致性判定方法的理论正确性和工程适用性。结果 MOSFET器件在温度低于240℃时,失效机理没有发生改变;温度高于240℃时,失效机理发生了改变,与前述失效机理不一致。结论基于失效物理的方法可以确定器件机理发生变化的温度应力点,所需样本量小。

Objective To save test sample and provide guarantee for efficiency of accelerated test by obtaining change point of failure mechanism in the POF-based accelerated life test. Methods Typical physical model of failure was applied to determine the change point of failure mechanism based on calculating the activation energy of MOSFET. And failure physical analysis was implemented to verify the theoretical correctness and engineering applicability of judgment method on consistency of failure mechanism from the micro perspective. Results When temperature was below 240 ℃, the failure mechanism did not change. And when the temperature was higher than 240 ℃, the failure mechanism changed. It was inconsistent with the above mentioned failure mechanism. Conclusion The POF method can confirm the temperature stress point of changed device mechanism and the required sample size is small.