Super-junction device and manufacturing method thereof

Abstract

The invention discloses a super-junction device, which is characterized in that a protective epoxy film exposes a charge flow region, completely covers a transition region and completely or mostly covers a terminal region, a second contact hole at the top of a P-type ring of the transition region is enabled to penetrate deeper than a first contact hole at the top of a P-type well of the charge flow region by the thickness of one protective epoxy film, and thus the junction depth of a second P+ contact region at the bottom of the second contact hole is enabled to be less than the junction depthof a first P+ contact region at the bottom of the first contact hole, so that the distance between a hole collected by the P-type ring to the second P+ contact region, and a softness factor of reverse recovery of a body diode of the device is increased. The invention further discloses a manufacturing method of the super-junction device. According to the invention, the reverse recovery characteristics of device can be improved, and the avalanche tolerance of the device is enhanced at the same time.

Description

Technical field [0001] The present invention relates to a method for manufacturing a semiconductor integrated circuit, in particular to a method for manufacturing a superjunction device. Background technique [0002] The super junction structure is a structure composed of alternately arranged N-type pillars and P-type pillars. If a super junction structure is used to replace the N-type drift region in a vertical double-diffused metal-oxide-semiconductor (VDMOS) device, a conduction path is provided through the N-type pillar in the conduction state. The P-type pillar does not provide a conduction path; in the off state, the PN pillar jointly bears the reverse bias voltage to form a Superjunction Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET). Super-junction MOSFET can greatly reduce the on-resistance of the device by using a low-resistivity epitaxial layer when the reverse breakdown voltage is the same as that of the traditional VDMOS device. [0003] In the existing s...

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Problems solved by technology

However, since the P+ contact region in the P-type ring in the transition region is also very dense, the ability to collect holes under the forward Vds is very strong, so the process of the body diode of the device from normal conduction to reverse bias is immediate During the reverse recovery process, since the holes are quickly drawn out through the P+ region through the contact hole, the reverse recovery is very fast and the softness factor is poor

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