Thick-film SOI-LIGBT device and method for improving latch-up resistance thereof

Abstract

The invention provides a thick-film SOI-LIGBT device and a method for improving latch-up resistance thereof. The device comprises a P-type substrate. A buried oxide layer is arranged on the P-type substrate. An N-type drift region is arranged above the buried oxide layer. A P-type body region and an N-type buffer region are arranged inside the N-type drift region. A P-type cathode contact region and an n-type cathode contact region are provided on the surface of the P-type body region. The contact region is connected with the cathode contact metal layer. A P-type anode contact region is arranged on the surface of the N-type buffer region. The contact region is connected with the anode contact metal layer. A field oxide layer and a conductive polysilicon gate are arranged on the surface of the N-type drift region. Passivation layers are arranged on the surface of the cathode contact region, the anode contact region, the field oxide layer and the conductive polysilicon gate. The device is characterized in that an isolation trench is arranged on the outside of the cathode of the device; and conductive polysilicon in the isolation trench is shorted to the cathode contact region and the cathode metal layer. According to the method, the potential difference between the conductive polysilicon in the isolation trench and the N-type drift region is increased; hole current flowing through a lateral channel in the P-type body region is reduced; and the latch-up resistance is improved.

Description

technical field [0001] The invention relates to the reliability field of integrated circuits, and relates to a thick-film SOI-LIGBT device and a method for improving its anti-latch ability. Background technique [0002] High-power semiconductor devices and integrated circuits have accounted for about 75% of the total value of the international power semiconductor industry. my country's independent research and development of high-power device technology is also gradually internationalized. At the same time, reliability issues such as overheating, overvoltage, electrostatic protection (ElectronicStatic Discharge protection, ESD), and anti-latch-up of devices are also particularly prominent. Among them, the overcurrent problem caused by the latch-up effect makes the insulated gate bipolar transistor (Insulated Gate Bipolar Transistor, IGBT), silicon-on-insulator lateral insulated gate bipolar transistor (Silicon-On-Insulated-Lateral Insulated Gate Bipolar Transistor, SOI- LIG...

AI Technical Summary

Problems solved by technology

The hole current is sent from the anode and flows through the N-type buffer zone, N-type drift region and P-type body region, and finally collected by the cathode P-type contact region; when the hole current is too large, it will flow through the lateral groove in the P-type body region When the voltage drop in the channel area reaches 0.7V, the parasitic NPN transistor is turned on. At this time, the parasitic NPN transistor and the PNP transistor at the collector provide base current to each other, so that the device cannot be turned off, and finally a latch-up phenomenon is formed.

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