A Termination Structure for Improving Avalanche Tolerance of Superjunction Power Devices

A terminal structure, avalanche tolerance technology, applied in semiconductor devices, electrical components, thyristors, etc., can solve problems such as poor avalanche tolerance, improve reliability, avoid parasitic BJT conduction problems, and avoid the effect of long avalanche current paths

CN103996702BInactive Publication Date: 2017-03-01UNIV OF ELECTRONICS SCI & TECH OF CHINA
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2017-03-01
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention relates to semiconductor technology, in particular to a terminal structure for improving the avalanche tolerance of a superjunction power device. The invention proposes a terminal breakdown area in the device terminal area, and limits the avalanche breakdown point in the terminal breakdown area, thereby not only avoiding the parasitic BJT conduction problem of cell breakdown, but also avoiding the problem of conventional terminal breakdown. The avalanche current path is too long, causing the problem of local temperature rise, so the avalanche tolerance and reliability of the superjunction power device can be improved. The beneficial effects of the invention are that the avalanche current path of the device when the avalanche breakdown point is at the terminal is effectively shortened, the resistance to UIS failure of the device is improved on the premise of not affecting the breakdown voltage of the device, and the reliability of the device is improved . The present invention is particularly applicable to superjunction power devices.
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Description

technical field

[0001] The invention relates to semiconductor technology, in particular to a terminal structure for improving the avalanche tolerance of super-junction power devices. Background technique

[0002] Power MOSFET (Metal Oxide Semiconductor Field Effect Transistor) plays an important role in various power conversions, especially in high-frequency power conversions, due to its advantages of high switching speed, low switching loss, and low driving loss. The switching process under an unclamped inductive load (Unclamped Inductive Switching, UIS) is generally considered to be the most extreme electrical stress situation that power devices can encounter in system applications. Because the energy stored in the inductor must be released by the power device at the moment of turn-off when the loop is turned on, and the high voltage and high current applied to the power device can easily cause the device to fail. Avalanche endurance is an important parameter to measure t...

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Embodiment Construction

[0023] Below in conjunction with accompanying drawing and embodiment, describe technical solution of the present invention in detail:

[0024] Such as figure 1 As shown, it is a schematic diagram of the terminal structure of a common super-junction MOSFET. When the avalanche breakdown of the device occurs at the terminal, the location of the breakdown point is random, and the avalanche current will flow from the breakdown point through the terminal surface to the source of the device. The farther the breakdown point is from the element cells, the longer the path of the avalanche current flows. Figure 4 This is the distribution diagram of the avalanche current at the terminal of a common super-junction MOSFET obtained by the simulation tools Tsuprem4 and Medic. It can be seen from the figure that the avalanche current will flow laterally through the surface of the terminal with a long path. The longer the avalanche current path, the greater the resistance of the avalanche cur...