Method for preparing gallium nitride based field-effect transistor

Abstract

The invention discloses a method of manufacturing GaN-based field-effect transistors, which includes steps of surface-finishing a GaN-based material layer, depositing a silicon oxide protective layer,forming lithographic alignment marks via lithography, dry-etching the silicon oxide protective layer, evaporating marked metal, forming source-drain patterns via lithography, dry-etching the siliconoxide protective layer, evaporating source-drain metal, annealing alloy at high temperature, forming shielding active region patterns via lithography, forming active region isolation via ion implantation, then wet-etching the silicon oxide protective layer, depositing silicon nitride on the surface of the GaN-based material, passivating field effect transistors, forming grids via electron-beam direct writing or optical lithography, dry-etching the silicon nitride and the GaN-based material layer at the top to form a gate-recessed structure, evaporating gate metal and metal wiring. The method of manufacturing GaN-based field-effect transistors avoids the surface of the GaN-based material being exposed in air, prevents the surface of the GaN-based material from being polluted during fabrication process, and inhibits current collapse effect of AlGaN / GaN HEMTs.

Description

technical field [0001] The invention relates to the technical field of wide-bandgap semiconductor material field effect transistors (FETs), in particular to a method for manufacturing gallium nitride (GaN)-based field effect transistors. Background technique [0002] As the third-generation wide-bandgap semiconductor material, GaN has a large bandgap (3.4eV), a high breakdown voltage (3.3MV / cm), a high concentration of two-dimensional electron gas (>1013cm2), and a large saturated electron velocity (2.8 X107cm / s) and other characteristics have received extensive attention internationally. At present, the high frequency, high voltage, high temperature and high power characteristics of AlGaN / GaN HEMT devices make them have great prospects in microwave power devices. [0003] For conventional GaN HEMT devices for X-band, the usual process steps are: [0004] Step 1. Electron beam direct writing lithography or ordinary optical lithography to form an electron beam alignment ...

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Problems solved by technology

[0019] Another object of the present invention is to provide a method for manufacturing a GaN-based field effect transistor to solve the problem of AlGaN surface contamination caused by carbon and oxygen caused by long-term exposure of the AlGaN surface in the air, and the increase of the AlGaN surface state density, thereby Effective suppression of AlGaN / GaN HEMT current collapse effect

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