Bipolar transistor and method of making same

Abstract

The invention relates to a bipolar transistor and a manufacturing method thereof. During formation of an emitter polycrystalline silicon, the manufacturing method comprises the following steps: forming second polycrystalline silicon layers on base region shallow junctions, on a silicon oxide layer, on an oxide layer and on an isolating side wall; forming an emitter junction on the surface of the base region shallow junction, forming a titanium nitride layer and a metal titanium layer on the second polycrystalline silicon layers, and performing rapid thermal annealing on the titanium nitride layer and the metal titanium layer; and removing the second polycrystalline silicon layers, the titanium nitride layer and the metal titanium layer on the oxide layer, the silicon oxide layer and the isolating side wall, wherein the second polycrystalline silicon layers as well as the titanium nitride layer and the metal titanium layer positioned on the base region shallow junction are taken as theemitter polycrystalline silicon. According to the method disclosed by the invention, the emitter polycrystalline silicon is formed in a manner of sequentially depositing the second polycrystalline silicon layers, the titanium nitride layer and the metal titanium layer, and the problem in the current process that base-emitter short circuit is caused due to too small size of the polycrystalline emitter is solved.

Description

【Technical field】 [0001] The invention relates to the technical field of semiconductor manufacturing technology, in particular to a bipolar transistor and a manufacturing method thereof. 【Background technique】 [0002] It originated from the point-contact transistor transistor invented in 1948, and developed into a junction transistor in the early 1950s, which is now called a bipolar transistor. There are two basic structures of bipolar transistors: PNP type and NPN type. In these three layers of semiconductors, the middle layer is called the base region, and the outer two layers are called the emitter region and the collector region. When a small amount of current is injected into the base region, a larger current will form between the emitter region and the collector region, which is the amplification effect of the transistor. In bipolar transistors, both electrons and holes conduct electricity. Compared with field effect transistors, bipolar transistors have slow switc...

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Problems solved by technology

[0004] 1. Emitter size problem: After the base polysilicon is etched, the distance between the base polysilicon on both sides is 0.8um. ​​After the isolation sidewall is completed, the distance between the isolation sidewall is only 0.2um (the thickness of the sidewall isolation is 0.3um), that is, the size of the emission area will become 0.2um, which may reduce the reliability of the device

[0005] 2. Thickness of emitter polysilicon: usually the thickness of emitter polysilicon is about 2200A

But the biggest problem with this solution is that the isolation sidewall between the base polysilicon and the emitter polysilicon becomes very thin, only about 0.1um, and after the emitter polysilicon is etched, it is very easy to cause a short circuit between the base and the emitter. also affect the reliability of the device

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