Terminal Protection Structure for Superjunction Devices

Abstract

The invention discloses a terminal protection structure of a super-junction device. A P-type column and an N-type column of a super-junction structure of a current flow area are in a bar-shaped structure and are parallel to each other. A part of super-junction structure in the terminal protection structure is formed through extending the P-type column and the N-type column of the current flow area along a length direction. Another part of super-junction structure in the terminal protection structure is formed by alternatively arranging a second P-type column and a second N-type column of the bar-shaped structure, wherein the second P-type column and the second N-type column are parallel to the P-type column and the N-type column of the current flow area. A field plate and a P-type ring are formed in a transition area. A cut-off ring is formed on an outermost end of a voltage bearing area. The P-type column and the N-type column of the super structure of the terminal protection structure are in a long strip shape without turns. An electric leakage characteristic and reliability of the device can be increased and a smallest terminal size can be used to acquire a high breakdown voltage.

Description

technical field [0001] The invention relates to a semiconductor integrated circuit, in particular to a terminal protection structure of a super junction device. Background technique [0002] The super junction structure is composed of alternately arranged N-type pillars and P-type pillars. If the superjunction structure is used to replace the N-type drift region in the vertical double-diffused MOS transistor (Vertical Double-diffused Metal-Oxide-Semiconductor, VDMOS) device, the conduction path is provided through the N-type column in the conduction state, and when the conduction The P-type column does not provide a conduction path; in the off state, the PN column jointly bears the reverse bias voltage, forming a super-junction metal-oxide-semiconductor field-effect transistor (Metal-Oxide-Semiconductor Field-Effect Transistor, MOSFET). The super-junction MOSFET can greatly reduce the on-resistance of the device by using a low-resistivity epitaxial layer when the reverse br...

AI Technical Summary

Problems solved by technology

[0008] like figure 1 As shown, in the terminal region, that is, in the 3rd region, the P-type pillar 203 and the N-type pillar 204 are ring structures connected end to end, and the P-type pillar 203 is generally filled with a P-type epitaxial layer after forming a trench in the N-type epitaxial layer. Silicon formation, in the trench filling process, the trench is prone to defects at the position of the bend (whether it is a right angle or a bend with a little curvature), and when there is a large electric field intensity in this area, the leakage characteristics are poor. With curved parts, there will be local charge balance, so that high breakdown voltage cannot be obtained, and the device leakage will be poor

In order to solve the problem of local charge balance, the existing technology is to carry out special design at the corner, such as adding small square P-pillars, but this is very difficult in process realization

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