LDMOS structure applicable to LED driving circuit

Abstract

The invention discloses an LDMOS structure applicable to an LED driving circuit and a manufacturing method of the LDMOS structure in order to increase a breakdown voltage and relates to the field of high-voltage devices in a semiconductor 60V BCD process, in particular to an LDMOS device structure with a metal field plate. On the condition of not changing the size of a device and having little influence on on-resistance and a saturation current, the LDMOS structure substantially increases the breakdown voltage of the device. The method comprises the steps of adjusting the size of a POLY field plate, the size of the metal field plate and the number of grid electrodes. As a result, performance parameters of the device are greatly improved.

Description

technical field [0001] The invention relates to the field of power devices, in particular to a lateral double-diffusion metal oxide semiconductor field effect transistor structure. Background technique [0002] Vertical double-diffused metal oxide semiconductor field effect transistor (VDMOS, Vertical Double-diffused MOSFET). Breakdown voltage is an important parameter to measure the performance of LDMOS devices. It usually means the maximum voltage that can be applied between the drain and gate of LDMOS without being broken down. [0003] With the advancement of technology, the breakdown voltage of LDMOS devices needs to be increased. The industry usually adds one or more wells in the drift region of LDMOS devices, where the pole type of the well is opposite to that of the drift region. For example, if the drift region is N-type, then The well is P-type. [0004] figure 1 It is a schematic diagram of the structure of an N-type LDMOS device in the prior art. Breakdown vol...

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Problems solved by technology

[0004] figure 1 It is a schematic diagram of the structure of an N-type LDMOS device in the prior art. The breakdown voltage and on-resistance are the main technical indicators to measure the performance of LDMOS. The traditional LDMOS structure extends the polycrystalline to the field oxide layer 11 in the drift region to act as a field plate In order to increase the breakdown voltage, increasing the length of the field plate 12 can improve the withstand voltage performance of the device, but it will increase the chip area and on-resistance, so there is a compromise between the withstand voltage and on-resistance of LDMOS

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