Double-layer sectioned SOI LIGBT device and manufacturing method thereof

Abstract

The invention discloses a double-layer sectioned SOI LIGBT device. The double-layer sectioned SOI LIGBT device comprises a silicon substrate; a first buried oxide layer and an N buried layer are sequentially arranged on the silicon substrate from left to right; the upper surface of the N buried layer is higher than the upper surface of the first buried oxide layer; a P buried layer is arranged on the first buried oxide layer; a second buried oxide layer is arranged on the N buried layer; the upper surface of the P buried layer and the upper surface of the second buried oxide layer are at the same height; and an N type drift region is arranged on the P buried layer and the second buried oxide layer. The invention also discloses a manufacturing method of the double-layer sectioned SOI LIGBT device. According to the manufacturing method, the oxide layer of a conventional SOI LIGBT is divided into two layers, and layers are separated from each other through reverse PN junctions; and with a novel sectionally-isolated structure adopted, excellent substrate leakage current isolation of the device can be ensured, heat dissipation performance can be improved, operating temperature can be decreased, and breakdown voltage can be improved.

Description

technical field [0001] The invention relates to the field of electronic technology, in particular to a double-layer partial SOIL IGBT device and a manufacturing method thereof. Background technique [0002] Lateral Insulated Gate Bipolar Transistor LIGBT (LateralInsulatorGateBipolarTransistor) is a composite power device that combines MOS gate device structure and bipolar transistor structure. It has the characteristics of high input impedance and low conduction voltage drop. The difference from LDMOS is that LIGBT is a bipolar device. When it is turned on, there is not only electron current, but the anode P+ will inject holes into the drift region to generate electron current. In the absence of an isolation layer, some holes will continue to flow to the substrate. injection, causing considerable leakage current. Therefore, there are two substrate isolation methods, one is the reverse PN junction plus a current-conducting structure. The disadvantage of this structure is tha...

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Problems solved by technology

The difference from LDMOS is that LIGBT is a bipolar device. When it is turned on, there is not only electron current, but the anode P+ will inject holes into the drift region to generate electron current. In the absence of an isolation layer, some holes will continue to flow to the substrate. injection, causing considerable leakage current

Therefore, there are two substrate isolation methods, one is the reverse PN junction plus a current-conducting structure. The disadvantage of this structure is that it requires heavy doping, which greatly reduces the breakdown voltage.

One is SOI isolation. In this way, the oxide layer is used to directly isolate the substrate and the drift region, which can effectively reduce the leakage current, but because only the drift region is under pressure, the breakdown voltage is also reduced. At the same time, because of the heat conduction of the oxide layer Poor capacity, can cause self-heating effect

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