Trench MOSFET integrated with ESD protection and manufacturing method thereof

Abstract

The invention discloses a more excellent trench MOSFET integrated with ESD protection and a manufacturing method thereof. The trench MOSFET integrated with ESD protection comprises a voltage stabilizing diode formed by connecting a positive PN junction and a negative PN junction in series between a grid electrode and a source electrode of the MOSFET, wherein one end of the voltage stabilizing diode is connected with the grid electrode of the MOSFET, and the other end of the voltage stabilizing diode is connected with the source electrode of the MOSFET. The trench MOSFET integrated with ESD protection comprises a voltage stabilizing diode formed by connecting a positive PN junction and a negative PN junction in series between the grid electrode and a drain electrode of the MOSFET, wherein one end of the voltage stabilizing diode is connected with the grid electrode of the MOSFET, and the other end of the voltage stabilizing diode is connected with the drain electrode of the MOSFET. In the manufacturing method of the trench MOSFET integrated with ESD protection, a P-type doped region of the voltage stabilizing diode integrated in the trench MOSFET and a P-type body region of the MOSFET can be synchronously formed in process, and an N-type doped region of the voltage stabilizing diode and an N-type source region of the MOSFET can be synchronously formed in process, so that lower manufacturing cost is realized.

Description

technical field [0001] The invention relates to the technical field of semiconductor device manufacturing, in particular to a trench MOSFET with integrated ESD protection and a manufacturing method. Background technique [0002] MOSFET chips are classified according to structure, including planar MOSFET and trench MOSFET. Among them, trench MOSFET occupies a dominant position in medium and low voltage MOSFETs due to its higher current density; MOSFET chips are classified according to conduction methods, including N-type MOSFET and P-type MOSFETs, where N-type MOSFETs are more widely used due to their higher current density. MOSFET chips include three ports: source, gate, and drain. Usually, the source and gate are on the front of the chip, and the drain is on the back of the chip. [0003] There is a thin gate oxide layer between the gate and the source and drain of the MOSFET chip, which will be damaged by breakdown and cannot be recovered when it is subjected to an unexpe...

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Problems solved by technology

[0007] 1. In order to make thick oxide layer and polysilicon diode, the process flow is more complicated and the process cost is higher

[0008] 2. Due to the thick oxide layer and polysilicon diodes, the step difference on the chip surface is relatively large, which increases the difficulty of the process and poor process stability

[0009] 3. The Zener diode uses polysilicon diodes, and polysilicon is composed of silicon grains of a certain size. Its stability and consistency are worse than those of single crystal silicon. Therefore, Zener diodes made of polysilicon have better ESD protection capabilities. The stability is also poor

[0010] 4. The Zener diode is located between the gate and the source, not between the gate and the drain, so the ESD energy between the gate and the drain can only pass through the Zener diode and the body of the MOSFET The series loop composed of parasitic diodes discharges, that is, the ESD energy discharge channel between the gate and the drain has one more internal parasitic diode than the ESD energy discharge channel between the gate and the source, thereby increasing the energy discharge The clamping voltage and impedance of the channel, therefore, typically results in less ESD protection between gate and drain than between gate and source

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