Terminal structure of super-junction semiconductor device

Abstract

The invention belongs to the technical field of a longitudinal super-junction semiconductor device, and specifically relates to a terminal structure of a super-junction semiconductor device. According to the terminal structure provided by the invention, the width of the first conductive type semiconductor drifting strip is adjustable, and the width is gradually changed from a cellular region to the boundary, so that the terminal charge can be well balanced so as to improve the voltage withstand of the device; next, a second conductive type surface doping region constantly covers a second conductive type semiconductor column, and extends towards the boundary for a certain distance so as to ensure that the border position of the two types of semiconductor drifting regions is fully covered to lower the surface peak electric field; and the first conductive type surface doping region in the second conductive type surface doping regions provides a positive charge center downwardly to further lower the surface electric field of the device so as to lower the probability of surface breakdown of the super-junction terminal in order to improve the overall voltage withstand of the device.

Description

technical field [0001] The invention belongs to the technical field of power semiconductor devices, and in particular relates to a terminal structure of a super junction semiconductor device. Background technique [0002] The proposal of the super junction breaks the silicon limit relationship between the traditional withstand voltage and the specific conductance to the power of 2.5, and the device has a lower specific on-resistance at the same time as the high withstand voltage. According to the superjunction theory, increasing the doping concentration of the PN strips in the drift region can effectively reduce the specific on-resistance of the device, and reducing the width of the PN strips can make the depletion between the PN strips more complete, thereby increasing the withstand voltage. Therefore, the cell design of most superjunction devices has the characteristics of high doping concentration and small stripe width. However, the terminals of traditional super-juncti...

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Problems solved by technology

However, the terminals of traditional super-junction devices continue to use PN strips with the same spacing as the cells to withstand the withstand voltage. This kind of PN strips has high doping concentration and small spacing, often with low tolerance. Depletion is prone to breakdown due to terminal charge imbalance

Moreover, the concentration of PN strips is high, the slope of the electric field on the PN junction is large, and the difference between the peak and valley values ​​of the electric field is large, so that the voltage during breakdown is very low, and it is difficult to reach the withstand voltage value of the device cell design.

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