Abstract: When a transistor dissipates power on work,its junction temperature distribution is commonly non-uniform.Based on a sub-transistor shunt connection model,by theoretical analog calculation and experiment,it is found that in a non-uniform junction temperature distribution,the current density of the high-temperature region is higher than that of the low-temperature region.The ratio of the current density of the high-temperature region to that of the low-temperature region increases with the decrease of the measuring current.This phenomenon is called the excessive thermotaxis effect of low current.Based on these characteristics,the uniformity of the junction temperature distribution is studied.

Key words: junction temperature, current density, uniformity of junction temperature, effective area, 有效面积