IGBT, a high-voltage high-power integrated circuit device, has a wide range of high-power switching applications such as mobile driving, power supply, railway transportation, industry control, etc. NPT-IGBT is a composite device of MOSFET and BJT.
Since NPT-IGBT usually operates at high voltage and high current, hot-carrier-induced degradation will be generated inside the device. Hot carriers with high energy will damage the oxide region of the device and the interface between silicon and silicon-dioxide, and increase the trap charge of the interface and the oxide region.
Although many researchers have described the issues on hot carriers of IGBT device, little literature is on the reliability of hot carrier of NPT-IGBT.
Kim Hak Bong, a section head at the Semiconductor Institute, has analyzed the degradation mechanisms due to the hot carrier effect in NPT-IGBT through the voltage stress measurement, TCAD simulation and charge pumping measurement.
He has concluded the following from the results. First, the device might have different degradation mechanisms under different gate voltage conditions. Second, when the gate voltage is relatively high, degradation is caused in three regions. The boundary state is generated in the body region, while the oxide layer trap charge is caused in the accumulation region, the field-oxide region and the drift region. Third, when the gate voltage is relatively low, the boundary state and the oxide layer trap charge are formed in the drift region and the degradation in the body region is relatively small.
If more information is needed, please refer to his paper “Analysis on Effect of Hot-Carrier-Induced Degradation of NPT-IGBT” in “Solid-State Electronics” (SCI).
© 2021 Kim Chaek University of Technology