Trench LDMOS transistor with convex extended buried oxide region

Abstract

The invention discloses a trench LDMOS transistor with a convex buried oxide layer. The buried oxide layer is located above the substrate layer; a silicon film layer is positioned above the buried oxide layer; the silicon film layer comprises a silicon body, a source region, a drain region, an oxidation trench, a convex extended buried oxide region and a drift region; the oxidation trench is located at the top of the silicon film layer and located between the silicon body and the drain region; the convex extended buried oxide region is positioned at the bottom of the silicon film layer; a device top layer is arranged above the silicon film layer and comprises a source electrode, a gate oxide layer, a gate electrode, an extended oxide layer and a drain electrode; the gate oxide layer is located above the channel and completely covers the channel; the gate electrode is located right above the gate oxide layer and completely covers the gate oxide layer; the extended oxide layer is positioned above the silicon film layer and is in contact with one side, far from the source electrode, of the gate oxide layer; and the drain electrode completely covers the drain region and is in contact with one side, far from the gate oxide layer, of the extended oxide layer. According to the invention, the electric field distribution is improved through the coupling between the oxidation trench and the convex extended buried oxide region, and the conduction resistance and the quality factor are more excellent.

Description

technical field [0001] The invention belongs to the field of semiconductor high-voltage power devices, and is a trench lateral double-diffused metal oxide semiconductor (Lateral Double-diffused Metal Oxide Semiconductor, LDMOS) transistor with a convex extended buried oxygen region. Background technique [0002] For high-voltage semiconductor devices, improving the trade-off relationship between breakdown voltage and on-resistance is an important research direction. Generally speaking, in order to improve the performance of high-voltage LDMOS transistors, higher breakdown voltage (BreakdownVoltage, BV) and lower on-resistance (On-resistance, R on ). For this reason, various LDMOS transistors such as dielectric field enhancement structure, trench structure, and field plate structure have appeared. Among them, the device with the trench structure can effectively adjust the electric field distribution in the drift region, and the oxidation trench acts as a lateral insulating ...

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Problems solved by technology

On the other hand, the oxide trench can reduce the device cell size, thereby reducing the on-resistance of the device

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