Technology Of Localized Lifetime Control In Conductivity Modulation Power Devices

Conductivity modulation power devices, such as IGBTs (Insulated Gate Bipolar Transistors), are extensively used in modem power electronic circuits. The switch speed of power devices t_off will be increased, during the forward voltage drop Vp decreasing, because of conductivity modulation effects. It causes the operating frequency of power devices limited and switch loss increased. So, how to improve the tradeoff relationship between turn-off time and forward voltage is a key problem in power devices. The localized carrier lifetime control method has been considered as an effective technology in power devices, to increase the turn-off time and improve the tradeoff relationship between turn-off time and forward voltage. Although the localized lifetime control in PIN and IGBT has been discussed experimentally and numerically in a number of papers, the details of the device physics and analysis models are still somewhat unclear and not reported, so further work is need. At present time, some multi-region localized lifetime control methods have been reported to improve the tradeoff relationship of t_off-V_F. The results of multi-region localized lifetime controls show that tradeoff relationship of t_off-V_F has been improved remarkably, because there is a large degree of freedom. However, analysis models of the devices under multi-region localized lifetime control are still not reported.The main work of this thesis is studying localized lifetime control technology, which improve the tradeoff relationship of t(off)-V_F in conductivity modulation power devices, including researching methods and mechanisms of localized lifetime control with low energy and high dose He⁺ ion implantation, proposing a novel high speed SOI-LIGBT with He⁺ ion implant localized lifetime control, proposing steady-state and transient state analytical models for conductivity modulation power devices with localized lifetime controlled.A novel method of localized lifetime control with low energy and high dose He⁺ ions implantation, which can improve the tradeoff relationship of t_off -V_F more effectively, has been experientially and numerically studied in this thesis. Furthermore, a model to characterize the relationship between deep energy level, defects density and excess carriers lifetime, has also been proposed.A new high speed SOI-LIGBT with low energy and high dose He⁺ ion implantation localized lifetime control is proposed in this thesis, to raise the turn-off speed of LIGBT. A localized lifetime controlled SOI-IGBT has been realized and...