Method for improving phosphorus diffusion uniformity of Insulated Gated Bipolar Transistor (IGBT)

Abstract

The invention discloses a method for improving a uniformity of a phosphorus diffusion of a IGBT. The method comprises the steps of heating a phosphorus diffusion furnace to a temperature: 680DEG C to 720 DEG C, introducing a nitrogen with a flow of 15 slm to 30 slm. A IGBT chip which needs the phosphorus diffusion is disposed at a vessel and the vessel is putted into a phosphorus diffusion furnace; the temperature is adjusted to 800DEG C to 850DEG C, the introducing flow of nitrogen is 15slm to 30slm and the introducing oxygen flow is 500sccm to 2000sccm, a APC pressure in furnace is maintained between 0.05KPA and 0.3KPA, therefore an oxidation barrier layer is formed on a surface of the IGBT chip. Maintaining a temperature, a pressure and a nitrogen flow unchanged, a first phosphorus diffusion is carried out. The method for improving phosphorus diffusion uniformity of IGBT is characterized by forming an oxidation barrier on the surface of the IGBT chip to improve the uniformity of the phosphorus diffusion.

Description

technical field [0001] The invention relates to the technical field of semiconductor device preparation, in particular to a method for improving the uniformity of IGBT phosphorus diffusion. Background technique [0002] Because the IGBT has the characteristics of high DMOS input impedance, fast switching speed, high operating frequency, easy voltage control, good thermal stability, simple drive circuit, and easy integration, the conductance modulation effect of collector hole injection greatly reduces the conductance on-resistance, reducing on-state power dissipation. At present, power IGBT has been widely used in frequency conversion household appliances, wind power generation, locomotive traction, smart grid and other fields. It is a power device with excellent performance and has a broad market prospect. The restrictive factor of its application is high cost, and its electrical performance may be further improved. Therefore, for public welfare researchers, how to improve...

AI Technical Summary

Problems solved by technology

In the prior art, the liquid phosphorus oxychloride source is mainly used as the doping source. Since the purpose of doping is mainly to form the concentration gradient difference of the PN junction, the index used to evaluate whether this process meets the requirements is relatively simple. Generally, Statistical monitoring average and uniformity for comparison

The biggest problem of this type of phosphorus diffusion process is poor uniformity. The diffusion method of phosphorus oxychloride liquid source has large range, discrete distribution and low repeatability whether it is within a chip, between chips or between batches. phenomenon, which in turn affects the product yield, resulting in longer production cycles, waste of raw materials and higher production costs

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