Investigation And Enhancement For Reliability Of Power Device-Dmos With Trench Structure

In this paper, a typical power management device-DMOS was performed a series of reliability test from industrial standard, such as BI, PCT, TC, HAST. The result revealed the impact to the reliability of device from wafer material, design, and manufacture process. Base on the characteristic of VDMOS: a. with the U-poly gate; b. the drain current ID was from up to down, the appointed condition (humidity, temperature, voltage/current, etc.) were applied to the samples. And the performance of specimen in reliability test will help to calculate the MTTF (=1.61Х107hrs, >acceptable life time: 7 years) at usage condition (55°C junction temperature, 60% related humidity), where the acceleration factor was defined by the experiment condition (junction temperature 150°C). With the analysis of failure units using SEM, Cross section, TEM, the result exhibited the weakness of the device’s structure, and more defect induced in the manufacture process. The experiment estimates the advantage or disadvantage of the new design, and which is very helpful on the quality and reliability improvement and process optimization.