Lateral insulated gate bipolar transistor

Abstract

A lateral insulated gate bipolar transistor includes a semiconductor substrate including a drift layer, a collector region, a channel layer, an emitter region, a gate insulating layer, a gate electrode, a collector electrode, an emitter electrode, and a barrier layer. The barrier layer is disposed along either side of the collector region and is located to a depth deeper than a bottom of the channel layer. The barrier layer has an impurity concentration that is higher than an impurity concentration of the drift layer. The barrier layer has a first end close to the collector region and a second end far from the collector region. The first end is located between the channel layer and the collector region, and the second end is located on the bottom of the channel layer.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]The present application is based on and claims priority to Japanese Patent Applications No. 2010-120545 filed on May 26, 2010, and No. 2010-219357 filed on Sep. 29, 2010, the contents of which are incorporated in their entirety herein by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to a lateral insulated gate bipolar transistor (lateral IGBT).[0004]2. Description of the Related Art[0005]Japanese Patent No. 3,522,983 (corresponding to U.S. Pat. No. 5,731,603 and referred to as a patent document 1 hereafter) discloses a lateral IGBT in which the number of channels is increased to reduce an on-voltage. The patent document 1 also discloses that preventing operation of a parasitic thyristor is important to improve a latch-up immunity. This is because a current density in silicon in a lateral IGBT is much higher than a current density in silicon in a vertical IGBT. In a vertical IGBT, b...

AI Technical Summary

Benefits of technology

[0009]In view of the foregoing problems, it is an object of the present invention to provide a lateral IGBT in which an on-voltage can be reduced, a breakdown endurance can be secured, and a switching speed can be increased at the same time.

[0011]In the lateral IGBT according to the first aspect, an on-voltage can be reduced with increasing a carrier concentration in the vicinity of an emitter by disposing the barrier layer. In addition, because the barrier layer is not disposed a between adjacent emitters, a turning-off time can be improved. Furthermore, a breakdown endurance at switching can be improved. Thus, in the lateral IGBT according to the first aspect, the on-voltage can be reduced, the breakdown endurance can be secured, and the switching speed can be increased at the same time.

[0013]Also in the lateral IGBT according to the second aspect, the on-voltage can be reduced, the breakdown endurance can be secured, and the switching speed can be increased at the same time.

[0015]Also in the lateral IGBT according to the third aspect, the on-voltage can be reduced, the breakdown endurance can be secured, and the switching speed can be increased at the same time.

[0017]Also in the lateral IGBT according to the fourth aspect, the on-voltage can be reduced, the breakdown endurance can be secured, and the switching speed can be increased at the same time.

Problems solved by technology

Because a current density in a lateral IGBT at operation is much higher than a current density in a vertical IGBT at operation, the lateral IGBT has difficulty in securing a breakdown endurance.

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