Monitoring of carrier lifetime distribution in high power semiconductor device technology

Non-uniform distribution of carrier lifetime over the area of power bipolar semiconductor devices results in a non-uniform distribution of on-state current density and switching loses. Consequently, it results in non-uniform temperature distribution which can negatively influence the device reliability. Several methods can be used for measuring carrier lifetime distribution both in starting single crystal material and in device structures after high-temperature processes. Advantages and disadvantages of individual methods and an optimum area of applications are discussed in this paper. This paper is mostly oriented on a possibility to use LBIC method for measuring carrier lifetime distribution in the bulk of high voltage large-area devices, especially N+NPP+ diode structures.