HEMT device with multi-metal gate structure and preparation method thereof

Abstract

The invention discloses an HEMT device with a multi-metal gate structure and a preparation method thereof. The device comprises an AlGaN/GaN epitaxy layer; the two ends of the upper surface of the AlGaN/GaN epitaxy layer are connected with a source electrode and a drain electrode respectively; a gate electrode is arranged between the source electrode and the drain electrode at the place close to the source electrode side; and a first layer of metal X of the gate electrode is deposited in an electron beam evaporation mode, a second layer of metal Y of the gate electrode is deposited in a magnetron sputtering mode, the work function of the second layer of metal Y of the gate electrode is higher than that of the first layer of metal X, photoetching is not needed, and a metal structure which is formed after the gate electrode is stripped and makes contact with (Al)GaN is Y/X/Y. The multi-metal gate structure is in contact with (Al)GaN, so that the electric field is redistributed, the peakvalue of the electric field at the gate edge near the drain is reduced, and the breakdown voltage of the device is improved; and meanwhile, the lower electric field peak value of the gate edge weakensgate injection electrons to form a virtual gate effect, so that current collapse of the device is reduced, and the dynamic performance of the device is improved.

Description

technical field [0001] The invention relates to the field of semiconductors, in particular to a HEMT device with a multi-metal gate structure and a preparation method thereof. Background technique [0002] GaN materials are widely used in high-frequency power amplifiers and high-voltage power switches due to their high electron mobility, low on-resistance, excellent heat dissipation capability, and high breakdown. At present, the breakdown voltage of GaN-based HEMT devices is far from the theoretical limit of GaN materials (3.4 MV / cm). Devices are often prone to breakdown between the gate and drain. How to reduce the height of the gate edge near the drain? The electric field peak will be beneficial to increase the breakdown voltage of the device. The most common method at present is to use a gate field plate or a source field plate to adjust the electric field distribution, thereby reducing the high electric field peak at the edge of the gate near the drain. On the other h...

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Problems solved by technology

However, the above-mentioned method of changing the angle of electron beam deposition is difficult to control accurately and has poor repeatability

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