Analysis On The Failure Mechanism Of High-voltage IGBT

Since the 80 s of the 20 th century, the modern power semiconductor technology have developed rapidly so far. As the representative of modern power device technology,the IGBT has a crucial role in promoting the development of traditional industry and high technology industry.IGBT is a hybrid power electronic device, and it has the advantages of high working frequency, simple driving circuit and good thermal stability, and it has been widely used in industrial control, smart grid, rail transportation, household appliances and other fields. In recent years, people draw more and more attentions to the power device failure problem. This paper is based on a project that is in cooperation with a semiconductor company in China. The main task of this project is the numerical model establishment of the field-stop IGBT chip and the IGBT module failure analysis. In addition, this task includes promoting the development of IGBT in China.1. On the basis of enough understanding to the IGBT’s structure, working principle,static and switching characteristics, this paper describes and summarizes the possible IGBT failure mechanism in detail. This paper also analyzes the latch-up failure and the avalanche breakdown failure deeply. For example, from the current filament which is produced by the IGBT dynamic avalanche, then a conclusion about that the essence of overvoltage failure is a high-heat failure process which is caused by the junction temperature’s increasing can be drawed.2. In this paper, a IGBT module is dissected for measurement and analysis. The chip of IGBT failure module is tested for its electrical characteristics, and the package is removed, and the failure point is located through the EMMI test. Then the chip is cutted,and the junction of it is dyed, and the structure of the IGBT chip is observed by SEM. In this process, a high voltage source table, scanning electron microscope, optical microscope and emission microscope are used. Finally, the failure reasons are gained and some suggestions for improvement are made. So the whole process of the IGBT failure analysis is completed.3. A failure analysis process which based on chip level and corresponding method of test analysis have been designed. A standardized criterion about IGBT module analysis is established. Some effective analysis means are offered for the possible relevant problems about IGBT chip in the process of producing, packaging andapplication in the future. It has certain guiding significance for IGBT chip failure analysis.