A kind of ldmos transistor and its forming method

Abstract

The present invention provides an LDMOS transistor and its forming method. The forming method of the LDMOS transistor includes: providing a substrate, forming a body region and a drift region in the substrate; forming a gate on the substrate at the junction of the body region and the drift region. The gate structure includes a gate layer, a first sidewall and a second sidewall; etching removes the second sidewall and exposes a sidewall of the gate layer; oxidizes the gate layer to form a first oxide layer Form the source region and the drain region, the drain region and the gate layer are adjacently arranged between the orthographic projections of the drift region, and the drain region and the orthographic projection of the gate structure on the substrate are adjacently arranged, which can reduce the The size of the small device and the reduction of the current path reduce the on-resistance of the LDMOS transistor, and the first oxide layer is formed on the side wall of the gate layer close to the drain region to increase the breakdown voltage, thereby achieving breakdown voltage and conduction The balance between the resistors reduces the loss of the LDMOS transistor and improves the output power and overall performance of the LDMOS transistor.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing technology, in particular to an LDMOS transistor and a forming method thereof. Background technique [0002] At present, LDMOS (Lateral double diffusion MOS, laterally diffused metal oxide semiconductor transistor) transistors are widely used in power devices. The research focus of LDMOS transistors is mainly focused on improving the breakdown voltage (breakdown voltage, BV) and reducing the on-resistance (on-resistance, Ron). [0003] For traditional LDMOS transistors, in order to increase the breakdown voltage, there is a long and low-concentration drift region between the source and drain regions. Due to the high resistance of the low-concentration drift region, the LDMOS transistor can withstand higher Breakdown voltage, but it brings high on-resistance of LDMOS transistors, which increases the loss of power devices. Contents of the invention [0004] The object of the present in...

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Problems solved by technology

[0003] For traditional LDMOS transistors, in order to increase the breakdown voltage, there is a long and low-concentration drift region between the source and drain regions. Due to the high resistance of the low-concentration drift region, the LDMOS transistor can withstand higher Breakdown voltage, but with it, the on-resistance of the LDMOS transistor is higher, which increases the loss of the power device

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