The Vdmos Device Reliability

VDMOS is now one of the most popular power semiconductor devices.Because of the advantages such as low price, high input impedance, fast switching speed, excellent frenquency characteristic and good thermal stability, VDMOS has a wide range of applications both militarily and in ordinary electrical industry.As VDMOS can be found almost in all kinds of electronic equipments and motors, the reliability of it got more and more attentions.In this article,the basic theory and three static characteristic parameters( V BR,V t h,R on)were illustrated in detail.And then experiments were done to investigate the reliability of 7575 which was all researched by PITL.First, three kinds of basic reliability tests known as high temperature storage life (HTSL), temperature circle, high temperature reverse bias (HTRB) and high temperature gate bias (HTGB) were done to all 100 samples to simulate the application of VDMOS in circumstance with high temperature.Parameters were gotten both before and after those experiments.When the experiments were over, dissected the fail samples to confirm the reasons of failure.Second,aiming to the application in a electromotion bicycle,a PCB panal was made to simulate how the VDMOS worked in a real motor controller.The different maximum voltages supply to the control circuit were obtained by doing several tests.Then with both light load and heavy load ,tests were done to get the number how many times VDMOS made the moter brake successfully.Compare to the instances of ST 75NF75,analyses were done to get how the VDMOS's characaristic parameters influent the experiment results and gave some pieces of suggestion on how to improve 7575's reliability.