Trench type insulated gate bipolar transistor and its manufacturing method

Abstract

A trench-type insulated gate bipolar transistor and a method for fabricating the same are provided. The trench-type insulated gate bipolar transistor comprises a collector layer (220), a drift layer (240), a base layer (250), an emitter layer (260), a groove (290), and a gate dielectric layer (291) and a gate electrode (292) formed in the groove (290). An upper surface of the gate electrode (292) in the groove (290) is etched back below an upper surface of the base layer (250), so that the emitter layer (260) is formed operable by inclined ion implantation. The method comprise a back etching step of the gate electrode (292) and a step to form the emitter layer (260) by use of the gate electrode (292) as a mask and inclined ion implantation. The trench-type insulated gate bipolar transistor fabricated by the method has a small on-resistance and can reduce the chip area.

Description

technical field [0001] The invention belongs to the technical field of insulated gate bipolar transistors (Insulated Gate Bipolar Transistor, IGBT), and relates to an IGBT with a sinking gate electrode and inclined ion implantation to form an emitter layer and a preparation method thereof. Background technique [0002] The IGBT is a common power device, which is one of the mainstream devices for high-current switching, and is widely used in high-voltage and high-current situations, for example, when the working voltage is 1200V. [0003] figure 1 The above is a schematic diagram of a unit structure of a punch-through (PunchThrough, PT) trench type IGBT in the prior art. In this embodiment, the PT trench type IGBT100 is formed on the N-substrate, and the N-substrate is partially used to form the drift layer 140; the back of the N-substrate is doped to form the collector layer 120, from the collector One side of the electrode (Collector) layer 120 leads out a metal electrode...

AI Technical Summary

Problems solved by technology

However, in the PT trench type IGBT100, in order to avoid the latch-up (Latch-up) effect, a sufficient area must be provided for the base region 152, therefore, the lateral width of the emitter layer 160 will result in the area of ​​the emitter layer 160 greatly increased, which in turn leads to an increase in the area of ​​the PT trench type IGBT100, and an excessively large area of ​​the emitter layer 160 also leads to an increase in the leakage current during turn-off

In addition, when the emitter layer 160 is formed by arsenic (As) doping with a low diffusion coefficient, although the area of ​​the emitter layer 160 is small enough, its depth is relatively short (for example, 0.5 microns), and the channel length L ch At least 4.5 microns, the on-resistance of the IGBT100 will therefore increase dramatically

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