Method of preparing groove semiconductor power device

Abstract

The invention discloses a method for preparing a groove semiconductor power device, the method comprising the steps of first eroding a P-type epitaxial layer on an N-type substrate by use of a groove mask to form a plurality of grooves; forming a gate oxide layer on an inner side wall of each groove and filling each gate oxide layer with polysilicon; then forming a PSG oxide layer on a side wall at the top of each groove and diffusing an N-type dopant in each PSG oxide layer through high temperature into the epitaxial layer to form an N-type source region 202; then depositing an interlayer dielectric on the surface of the epitaxial layer; eroding the interlayer dielectric by use of a contact hole mask to form an opening in the interlayer dielectric and injecting an N-type dopant to form an N-type source region 203; eroding the surface of the epitaxial layer later to form a contact hole groove; carrying out metal plugging filling on the contact hole groove and depositing a metal layer on the surface of a device; and carrying out metal eroding by use of a metal mask to form a metal cushion layer and connection wires. By adopting the method of preparing the groove semiconductor power device, preparation procedures of base region masking and source region masking are eliminated, and the preparation cost of the device is greatly reduced.

Description

technical field [0001] The invention relates to the technical field of semiconductor power discrete devices, in particular to a preparation method of a trench-type semiconductor power discrete device. Background technique [0002] At present, power MOSFET (Metal Oxide Semiconductor Field Effect Transistor, Metal Oxide Semiconductor Field Effect Transistor) has been widely used in various electronic and communication products, computers, consumer appliances, automobiles, etc. At the same time, it also has various applications in industry. [0003] Power semiconductor devices represented by power MOSFETs can effectively control high-frequency large currents due to their low on-resistance and high-speed switching. At the same time, power MOSFETs are being widely used as small power conversion components such as power amplifiers, power converters, low noise amplifiers, and some personal computer power supply switches and power circuits, which are characterized by low power consu...

AI Technical Summary

Problems solved by technology

[0005] In the existing trench power MOSFET design and manufacturing field, the base region and the source region of the MOSFET need to be introduced by the steps of base region mask and source region mask respectively. In order to reduce the manufacturing cost, some previous proposals, Such as an article published in the Japanese Journal of Applied Physics (Japanese Journal of Applied Physics Vol 47, No.3, 2008, pp.1507-1511), or US patent documents US20110233667, US20090085074, US20110233666, US077996427, etc., attempt to omit The device manufacturing method of the mask step of the base region or the source region, the steps are relatively complicated, it is not easy to generate, or its termination structure is not good, the breakdown voltage and reliability of the manufactured semiconductor device are relatively poor, or its source region The structure of the device is not good, so that the manufactured semiconductor device has a poor Figure of merit. The merit index is the low on-resistance of the device multiplied by the gate charge of the device

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