Lateral PNP transistor and the method of manufacturing the same

Abstract

The present invention relates to a lateral PNP transistor and the method of manufacturing the same. The medium doping N-type base area and the light doping P− collector area were first introduced in the structure before the formation of P+ doping emitter area and the collector area. The emitter-base-collector doping profile in the lateral and the base width of LPNP were similar to NPN. The designer can optimize the doping profile and area size of each area according to the request of the current gain (Hfe), collector-base breakdown voltage (BVceo), and Early voltage (VA) of LPNP transistor. These advantages may cause to reduce the area and enhance performance of the LPNP transistor.

Description

FIELD OF THE INVENTION [0001] This invention is related to a lateral PNP transistor and the method of manufacturing the same. The invented lateral PNP transistor is mainly aimed at power driver and power output application to reduce the chip area and enhance the performance of products. BACKGROUND OF THE INVENTION [0002] The common tendency of microelectronic circuit is to integrate more functions on the chip in order to increase the widely applications of electric circuit, reduce the size and power consumption of system, and lower the price of devices. Although the bipolar transistor and bipolar process technology do not suit all applications, they are some key foundations for other extended process technology, like BiCMOS and BiCDMOS, for a long time. [0003] Generally there is no good PNP transistor in most bipolar processes, because this process generally is designed to make the best performance of vertical NPN transistor. Although the vertical PNP may be added into the manufactu...

AI Technical Summary

Benefits of technology

[0010] Additional purpose of this invention is to enhance the performance of products by using LPNP without special and complicated circuit design.

[0011] Further, this invention uses a composite mask to do multiple diffusions by self-alignment. Thus, the mismatch of multiple alignments could be eliminated and the width of base and collector could be controlled accurately.

[0014] According to the defined method as described above, self-alignment process is proceeded to eliminate the misalignment between multi layers. Thus, the current gain (Hfe) of LPNP transistor can be optimized and accurately controlled by the doping concentration and depth of N-type base and P+ emitter which diffused by two times through the same doping window. Also, the collector-base breakdown voltage (BVceo) can be optimized and accurately controlled by the distance between collector window and emitter window which formed in one time, and P− collector doping concentration and depth.

Problems solved by technology

Generally there is no good PNP transistor in most bipolar processes, because this process generally is designed to make the best performance of vertical NPN transistor.

Although the vertical PNP may be added into the manufacturing process, it will increase the process complexity, number of mask, and cost.

Owing to the limitations of LPNP performance, either big area LPNP or complicated circuit design will be needed to satisfy the request of the product.

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