A kind of low vf power mosfet device and manufacturing method thereof

Abstract

The invention discloses a low VF power MOSFET device which is small in electric leakage and adjustable in VF value. The low VF power MOSFET device comprises a semiconductor substrate, wherein the surface of a first conduction type drift region on the upper portion of the semiconductor substrate is a first main face, and the surface of a first conduction type substrate on the lower portion of the semiconductor substrate is a second main face. At least one unit cell array area is arranged in the first conduction type drift region, and each unit cell array area comprises at least one MOS area and at least one SBD area, wherein the MOS area and the SBD area are respectively provided with a groove, a second conduction type trap which is shallower than the grooves is arranged between the adjacent grooves, and a first conduction type injection area is arranged above the second conduction type trap. An insulation medium layer covers the fist main face, the insulation medium layer is provided with a groove which penetrates into one groove of the SBD area and a contact hole which is placed between the adjacent grooves and penetrates into the second conduction type strap. First metal is deposited on the surface of the insulation medium layer and in the contact holes to form a source electrode. Second metal is deposited on the second main face to form a drain electrode.

Description

Technical field [0001] The invention relates to a power semiconductor device and a manufacturing method thereof, in particular to a power MOSFET device with an ultra-low VF value and a manufacturing method thereof. Background technique [0002] In electronic appliances, MOSFETs are usually used in power conversion applications. This application requires that the power MOSFET must have good AC characteristics, that is, the voltage drop (VF) of the parasitic body diode of the MOSFET must be sufficiently low. [0003] In order to improve the AC frequency characteristics of MOSFET, early adopters Figure 21 As shown in the method of using a separate power MOSFET device in parallel with a power Schottky diode 104, the power MOSFET device itself also has a parasitic body diode 102; in addition, some manufacturers combine power MOS chips with Schottky chips Parallel packaging is used in an integrated block. These methods can effectively reduce the reverse voltage drop of MOSFET devices, bu...

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Problems solved by technology

[0006] 2. Under the reverse bias voltage, the leakage between the devices is the leakage between the metal semiconductor, and its leakage current is much larger than the P-N junction leakage, resulting in large reverse leakage of the device, high power consumption and low reliability

[0007] 3. Once the type of metal used as the source is selected, the VF value of the Schottky contact is fixed, and the value of VF can only be adjusted by changing the type of metal, and the process is not flexible enough

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