关于塑封VDMOS器件热点的研究

Research on hot spots of plastic package VDMOS devices

功率VDMOS器件作为新一代高压大电流功率器件兼有双极晶体管和普通MOS器件的优点,广泛应用于各个领域。由于功率VDMOS的工作条件恶劣,在高温大电压的应用环境下失效概率较大。在所有的失效机制中,很大一部分是由于器件无法承受瞬间高压脉冲,致使器件芯片烧坏失效。表现出的是在芯片某处产生一明显的烧穿点即所谓的"热点"。这里主要介绍了塑封VDMOS器件进行单雪崩能量测试过程和实际应用中不良品产生热点的原因,从二次击穿的角度对其进行理论解释并提出一些改进措施。

As a new generation of high-voltage and high-current power devices,VDMOS devices have both advantages of bi-polar transistors and general MOS devices,and are widely used in various areas. The failure probability of VDMOS is bigger un-der the high temperature and high voltage application environment due to its bad working conditions. In all the failure mecha-nism,the device chips′ burnout is mainly caused by instantaneous high-voltage pulse,to which the device can＇t afford. It will produce an obvious burn-through point on a chip,which is so-called “hot spot”. The reason why the so-called “hot spots” appear on defective products in the process of single avalanche energy testing or practical application of VDMOS devices is described in this paper. The theoretical explanation is made in the view of the secondary breakdown. Some improving measures are put for-ward.