A terminal structure of a super junction semiconductor device

Abstract

The invention belongs to the technical field of vertical super-junction semiconductor devices, and in particular relates to a terminal structure of a super-junction semiconductor device. In the terminal structure of the present invention, the width of the first conductive type semiconductor drift bar can be adjusted to achieve a gradual change from the cell region to the boundary, so that the terminal charges can be better balanced, thereby improving the withstand voltage of the device; The surface doping region of one conductivity type always covers the semiconductor column of the second conductivity type and extends to the boundary to ensure that the junction position of the two types of semiconductor drift regions is completely covered and the surface peak electric field is reduced. The second conductivity type The surface doping region of the first conductivity type in the surface doping region provides a positive charge center downward, which further reduces the surface electric field of the device, thereby reducing the probability of breakdown on the surface of the superjunction terminal and improving the overall withstand voltage 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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