Forwardly and reversely symmetrical P-type radial varying doping and similar table-board negative angle shaped junction terminal thyristor

Abstract

The invention relates to a forwardly and reversely symmetrical P-type radial varying doping and similar table-board negative angle shaped junction terminal thyristor. A higher concentration P-type doped layer forms a high-low junction which is a non-parallel plane junction on a low-concentration P-type doped layer; a junction surface bends to prevent higher concentration P-type impurities from entering junction terminal areas; and the edges of the forward and reverse junction terminal areas have similar table-board negative angle shapes. The forwardly and reversely symmetrical P-type radial varying doping has an effect of thinning P-area from double sides; and the forwardly and reversely symmetrical similar table-board negative angle shapes have effects of thinning a long base area, reducing occupied area per se, increasing cathode area and balancing forward and reverse voltage resistance. The forwardly and reversely symmetrical P-type radial varying doping and similar table-board negative angle shaped junction terminal thyristor has the characteristics of symmetrical forward and reverse block voltages, no additional thickness of long and short base areas and maximum cathode area. Compared with the thyristor made from an original silicon material with the same resistivity and diameter, the forwardly and reversely symmetrical P-type radial varying doping and similar table-board negative angle shaped junction terminal thyristor has the advantages of highest blocking voltage, highest ratio of breakover voltage to chip thickness and maximum cathode area.

Description

technical field [0001] The invention relates to the technical field of semiconductor power electronics, and is a forward and reverse symmetrical P-type radially variable doping and mesa-like negative-angle shaped junction terminal thyristor with special doping and shaped junction terminals. Background technique [0002] There are currently two types of UHV high-power bidirectional blocking silicon thyristor junction terminals known: 1. Forward P-type radial variable doping, mesa-like negative-angle shape, and reverse positive-angle shape (hereinafter referred to as I-type). Its disadvantages are as follows: ①The asymmetry of the forward and reverse shape causes the asymmetry of the forward and reverse blocking voltage of the thyristor. ② Positive angle molding will inevitably introduce an additional long base region (N region) to obtain a certain reverse blocking voltage to increase the thickness of the film. ③From the edge of the chip to the inside, the reverse positive an...

AI Technical Summary

Problems solved by technology

Its disadvantages are as follows: ①Asymmetric forward and reverse shapes cause asymmetric forward and reverse blocking voltages of thyristors

Its disadvantages are as follows: ①The higher concentration of P-type impurities partially submerges the low concentration region on the surface of the negative angle shape terminal region

Considering the need for space charge region broadening, the low concentration of P - The depth of type diffusion must be large enough, the manufacturing process takes a long time and introduces an additional short base area and anode surface P - additional slice thickness

② Occupies a large area and loses too much cathode area

The modeling area occupies a large area, and the loss of cathode area leads to a decrease in flow capacity

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