Method for improving etching repeatability of gallium nitride (GaN) high electron mobility transistor (HEMT) grid trench

Abstract

The invention discloses a method for improving the etching repeatability of a gallium nitride (GaN) high electron mobility transistor (HEMT) grid trench. The method comprises the following steps of: enlarging the size of the inner diameter of an inductively coupled plasma (ICP) tray; increasing the height of the ICP tray; and bonding a GaN epitaxial slice to be etched on slide glass and etching the grid trench. By the method, the influence of the thickness of the GaN epitaxial slice on grid trench etching can be eliminated, the plasma bombardment damage during GaN HEMT grid trench etching is reduced and direct current and high frequency characteristics of a device can be improved by enlarging a plasma distribution volume in a reaction cavity body of an ICP etcher, reducing the density of plasmas and shortening an acceleration distance of the plasmas.

Description

technical field [0001] The invention relates to the technical field of semiconductor devices, in particular to a method for improving the repeatability of GaN HEMT gate groove etching. Background technique [0002] As a wide-bandgap compound semiconductor material device, GaN HEMT has the characteristics of high output power and high temperature resistance, and has broad application prospects. Gate trench etching technology, as an effective means to improve the transconductance of GaN HEMT devices and increase the power output, has been widely used in the production process of GaN HEMT devices. However, since the GaN cap layer that needs to be etched away is very thin, and the two-dimensional electron gas is also easily damaged by etching, this requires the gate groove etching to have the characteristics of shallow distance and low damage, and also requires good uniformity. and repeatability. [0003] The gate trench etching process of GaN HEMT devices is very sensitive to...

AI Technical Summary

Problems solved by technology

[0003] The gate groove etching process of GaN HEMT devices is very sensitive to the etching conditions. The thickness of the GaN epitaxial wafer will affect the distance between the epitaxial wafer and the upper plate of the ICP chamber, thereby affecting the gate groove etching rate.

Therefore, the thickness variation of different regions on the same GaN epitaxial wafer will cause uneven etching depth of the gate groove, and the thickness variation of different batches of GaN epitaxial wafers will cause non-repetition of the gate groove etching

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