IGBT (Insulated Gate Bipolar Transistor) and manufacture method thereof

Abstract

Provided is an IGBT and a manufacture method thereof. The IGBT is formed on a semiconductor substrate, and comprises an MOS structure placed at the surface of the semiconductor substrate and a PN junction placed at the bottom of the semiconductor substrate. Multiple grooved structures are placed at the bottom of the semiconductor substrate, penetrate P and N zones of the PN junction, and divide the PN junction into multiple areas. Each grooved structure comprises a metal block at the bottom of the semiconductor substrate and an oxidation layer between the metal block and the semiconductor substrate, and the work function of metal of the metal block is lower than that of a material of the semiconductor substrate. The grooved structures enable that the direction and distribution of electronic current and hole current in the PN junction of the semiconductor substrate are changed, distribution of carriers in the semiconductor substrate can be adjusted by adjusting the grooved structures, and thus, the relation between the connecting voltage drop and turnoff time of the IGBT can be optimized.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to an insulated gate bipolar transistor and a manufacturing method thereof. Background technique [0002] IGBT (Insulated Gate Bipolar Transistor, insulated gate bipolar transistor) is composed of MOS (metal-oxide-semiconductor, insulated gate field effect transistor) and BJT (Bipolar Junction Transistor, bipolar transistor) located under the MOS channel Composite fully controlled voltage-driven power semiconductor device. It has the characteristics of high input impedance, small switching loss, fast speed, low voltage drive power, etc., and is widely used in high voltage, high current, high power and medium to high frequency occasions. [0003] However, due to the introduction of the PN junction hole injection mechanism of the IGBT substrate, the IGBT also has two problems: [0004] 1. There is a parasitic thyristor structure inside the device. Under certain conditions, th...

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Problems solved by technology

[0004] 1. There is a parasitic thyristor structure inside the device. Under certain conditions, the device is prone to latch-up effect and loses control ability, which reduces the safe working area and causes device failure; therefore, the design and preparation of the PN junction in the IGBT substrate has a great impact on device performance. and reliability performance have a very important impact on

[0005] 2. Due to the conductance modulation, a large number of electron-hole pairs are stored in the N drift region. It takes a certain time for a large amount of excess carriers to be completely extracted and recombined when turned off, which will cause a long current tail in the device and cause the device to switch. The loss increases, and the operating frequency is much lower than that of VDMOS, which limits its application in the high frequency field

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