Metallic oxide semiconductor field effect tube semiconductor device

Abstract

A power MOSFET semiconductor device high in breakdown voltage and low in resistance can be manufactured at a low cost and in a short turnaround time. In a planar-type power MOSFET, a manufacture method comprises forming a trench in a drift region, and forming a body diffusion layer on a trench side wall and bottom portion (forming the trench and subsequently performing diffusion) to obtain a structure. Deep body diffusion formation is effective for obtaining the high breakdown voltage and low resistance, but to attain the structure, usually epitaxial growth and selective formation of a deep body region have to be performed a plurality of times, and with an increase of manufacture steps, souring of manufacture cost and lengthening of manufacture period are caused. However, the present structure can further simply bring about the similar effect.

Description

technical field [0001] The invention relates to a structure of a power MOSFET (Metal Oxide Semiconductor Field Effect Transistor) semiconductor device with high withstand voltage and low resistance and a manufacturing method of the structure. Background technique [0002] Figure 6 is a cross-sectional view of a conventional power MOSFET. In order to achieve a high withstand voltage and a low on-resistance, a so-called bulk diffusion is introduced locally in the drift region of the drain of the structure. During the off time of the MOSFET, a void layer extends from both sides of the deep body diffusion to touch each other in the middle. Specifically, in this case, the drift region under the gate becomes a blank layer up to a depth substantially equal to the depth of the deep body diffusion. Since the width of the blank layer is very large, the electric field relaxation effect is large, so the withstand voltage can be improved without reducing the impurity concentration in t...

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Problems solved by technology

[0003] However, in order to realize the traditional structure, the epitaxial growth and selective formation of the deep body region must be performed multiple times, and the manufacturing process is increased, resulting in a sharp increase in manufacturing costs and a prolonged manufacturing cycle

[0004] For example, when a drain withstand voltage of several hundreds of volts or more is realized, a thickness of 5 to 12 micrometers is required for the deep body region, but, in this case, the epitaxial growth and selective formation of the deep body region need to be repeated for about 6 times

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