Super junction mos bipolar transistor and process of manufacture

Abstract

Methods and designs are provided for a vertical power semiconductor switch having an IGBT-with-built-in-diode bottom-side structure combined with a SJMOS topside structure in such a way as to provide fast switching with low switching losses (MOSFET), low on-resistance at low currents (SJMOS), low on-resistance at high currents (IGBT), and high current-density capability (IGBT).

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application is a continuation of U.S. application Ser. No. 15 / 912,400, filed Mar. 5, 2018, now U.S. Pat. No. 10,580,884, granted on Mar. 3, 2020, which claims priority to U.S. Provisional Application No. 62 / 468,726, filed Mar. 8, 2017. Each patent application identified above is incorporated here by reference in its entirety to provide continuity of disclosure.TECHNICAL FIELD OF THE INVENTION[0002]This invention relates generally to increasing the energy efficiency, reducing the switching time, and increasing the current-carrying capability of a power semiconductor switch by optimal combination and design of a merged SuperJunction MOSFET-IGBT transistor. In particular, this invention details methods and designs for a vertical power semiconductor switch having an IGBT-with-built-in-diode bottom-side structure combined with a SJMOS topside structure in such a way as to provide fast switching with low switching losses (MOSFET), low on-r...

AI Technical Summary

Benefits of technology

The invention is a new type of semiconductor switch called the SJMOSBT that has faster switching and lower energy losses compared to an IGBT. It uses a special technique called charge-balancing to reduce energy loss and the need for additional processing steps like irradiation or metal deposition. The SJMOSBT combines the characteristics of a MOSFET and an IGBT to achieve superior performance. It also reduces the need for a separate heat sink, which makes it more efficient and cost-effective.

Problems solved by technology

When designing power supplies and power conversion systems, significant compromises in energy efficiency must be made in power switch device selection due to the limitations imposed by the switching characteristics of the available switching elements.

A MOSFET is capable of fast switching and hence low switching losses, but has limited current-density capability, both of which are due to the majority-carrier nature of the device.

An IGBT, on the other hand, is a minority-carrier device which can achieve very high current-density but is limited in switching speed by minority-carrier-lifetime-induced tail current which results in extended turn-off time and thus higher switch-off energy loss compared to the MOSFET.

The switching speed of a standalone IGBT is usually limited by the turn-off tail current.

Lifetime control is often done in IGBTs by using irradiation or implants or heavy metals to create recombination centers; however, the use of such techniques is quite limited as they trade off tail-current reduction for significantly increased off-state leakage and increased on-state energy loss, both of which add to the DC energy loss of the switch.

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