CN212209500U - Has Ga2O3/Al2O3HEMT device of protective layer - Google Patents

Abstract

The utility model discloses a Ga₂O₃/Al₂O₃A HEMT device of the protective layer. The device comprises AlGaN/GaN epitaxy, wherein two ends of the upper surface of the AlGaN/GaN epitaxy are respectively connected with a source drain electrode, the source drain electrode adopts a method combining electron beam evaporation and magnetron sputtering, and the whole wafer is subjected to N before the source drain electrode is subjected to high-temperature annealing₂O plasma treatment to form Ga₂O₃/Al₂O₃And after the protective layer is formed, performing a high-temperature annealing process, and arranging a gate electrode on the source and drain electrodes close to the source electrode side. Ga₂O₃/Al₂O₃The protective layer effectively inhibits an interface state introduced to the surface of the (Al) GaN in the high-temperature annealing process, and N₂The O plasma treatment process has no deterioration effect on the annealing effect of the source and drain electrodes. The organic compound has Ga₂O₃/Al₂O₃The HEMT device of the protective layer has low interface state density and excellent high-frequency and dynamic characteristics.

Description

Has Ga2O3/Al2O3HEMT device of protective layer

Technical Field

The utility model relates to a semiconductor field AlGaN/GaN HEMT device, in particular to have Ga₂O₃/Al₂O₃A HEMT device of the protective layer.

Background

Because of the characteristics of high electron mobility, low on-resistance, excellent heat dissipation capability, high breakdown and the like, the GaN material is widely applied to occasions such as high-frequency power amplifiers, high-voltage power switches and the like. At present, the formation of the ohmic contact of the GaN HEMT device depends on a high-temperature annealing process (generally over 800 ℃), and the high-temperature annealing process is caused by N₂The purity and the vacuum degree of the chamber are not free of O in the whole chamber atmosphere₂And H₂O, etc. exist, so that an oxidation reaction occurs on the (Al) GaN surface during high-temperature annealing, so that the surface states of the device increase, resulting in degradation of the dynamic performance of the device (t. Hashizume, et Al, appl. surf. sci., 2004, 234 (1-4)).

Some researchers have proposed the method of laser annealing of the source-drain electrode region (m. Hou, et al, electron. lett., 2019, 55 (11)) for this problem, this method has avoided the place beyond the source-drain electrode to participate in the annealing process, have optimized the dynamic resistance of the device; but presents self-alignment and cost issues that make it difficult to use in bulk.

N₂O plasma treatment is currently widely used for (Al) GaNMethod of oxidation of the interface by which a thin layer of Ga is formed at the (Al) GaN interface₂O₃/Al₂O₃The oxide film is capable of effectively protecting the (Al) GaN interface, effectively suppressing current collapse, and reducing parasitic parameters (M, H, et Al, AIP adv., 2019, 9 (04)).

In summary, N₂The O plasma treatment enables Ga to be formed₂O₃/Al₂O₃The film can be used as a passivation layer of the device. The film deposited by the traditional CVD method and other methods is usually prepared at the temperature below 800 ℃, and the film is easy to crack after high-temperature annealing, so that the reliability of the device is degraded, and therefore, the traditional passivation process is carried out after the high-temperature annealing process; however, passivation before high-temperature annealing is advantageous to prevent the above-mentioned oxidation reaction on the surface of (Al) GaN during high-temperature annealing from degrading the dynamic properties. Therefore, the utility model adopts N₂Formation of Ga by O plasma treatment₂O₃/Al₂O₃The passivation layer is formed on the surface of the (Al) GaN material directly, and a better film interface can be kept after high-temperature annealing, so that the interface state introduced in the high-temperature annealing process is inhibited, the interface passivation protection effect is also realized, and the dynamic characteristic of a device is improved.

SUMMERY OF THE UTILITY MODEL

In order to solve the problems existing in the prior art, the present invention provides a Ga-containing lamp having a structure of Ga₂O₃/Al₂O₃An HEMT device with a protective layer and a preparation method thereof. The device adopts Ga₂O₃/Al₂O₃The protective layer structure effectively reduces or avoids interface states introduced to the (Al) GaN interface in the high-temperature annealing process, inhibits current collapse, reduces electric leakage and improves the dynamic performance of the device.

The Ga is₂O₃/Al₂O₃The formation of the protective layer is mainly to carry out N on the whole wafer before the high-temperature annealing of the source and drain electrodes₂Obtained after O plasma treatment.

The object of the utility model is achieved by at least one of the following technical solutions.

The utility model provides a Ga-containing₂O₃/Al₂O₃The HEMT device comprises AlGaN/GaN epitaxy, two ends of the upper surface of the AlGaN/GaN epitaxy are respectively connected with a source drain electrode, the source drain electrode adopts a method of combining electron beam evaporation and magnetron sputtering, and the whole wafer is subjected to N before the source drain electrode is annealed at high temperature (more than 800℃)₂O plasma treatment to form Ga₂O₃/Al₂O₃And after the protective layer, performing a high-temperature annealing process, wherein a gate electrode is arranged on the source electrode side close to the source electrode side.

The utility model provides a pair of have Ga₂O₃/Al₂O₃The HEMT device of the protective layer comprises AlGaN/GaN epitaxy, source and drain electrodes and Ga₂O₃/Al₂O₃A protective layer and a gate electrode; two ends of the upper surface of the AlGaN/GaN epitaxy are respectively connected with a source drain electrode; the Ga is₂O₃/Al₂O₃The protective layer is laminated on the AlGaN/GaN epitaxy; the gate electrode is arranged at Ga₂O₃/Al₂O₃On the protective layer.

Further, the distance from the gate electrode to the source electrode is smaller than the distance from the gate electrode to the drain electrode, that is, the gate electrode is disposed on the source electrode close to the source electrode.

Further, the Ga is₂O₃/Al₂O₃The thickness of the protective layer is 3-5 nm.

The utility model provides a preparation of Ga₂O₃/Al₂O₃The method for protecting the HEMT device comprises the following steps:

(1) performing mesa isolation on AlGaN/GaN epitaxy, defining a source and drain electrode region, and depositing a source and drain electrode;

(2) after the source/drain electrode is stripped, N is performed₂O plasma treatment to obtain Ga₂O₃/Al₂O₃A high-temperature annealing process is carried out on the protective layer after the treatment; finally, defining a gate region, and depositing a gate electrode to obtain the semiconductor device with Ga₂O₃/Al₂O₃A HEMT device of the protective layer.

Further, step (2) of said N₂The O plasma treatment is carried out in a Plasma Enhanced Chemical Vapor Deposition (PECVD).

Further, step (2) of said N₂The specific process conditions of O plasma treatment are as follows: n is a radical of₂The flow rate of O is 50-150 sccm, the power is 100-300W, the pressure of the cavity is 600-800 mTorr, the temperature is 200-300 ℃, and the processing time is 10-30 min.

Further, the temperature of the high-temperature annealing process in the step (2) exceeds 800 ℃.

The utility model discloses carry out N with whole wafer before source leakage electrode high temperature annealing₂O plasma treatment to form Ga₂O₃/Al₂O₃And after the protective layer, performing a high-temperature annealing process, wherein a gate electrode is arranged on the source electrode side close to the source electrode side.

Compared with the prior art, the utility model has the following beneficial effect and advantage:

the utility model adopts Ga₂O₃/Al₂O₃The protective layer structure effectively reduces or avoids interface states introduced to the (Al) GaN surface in a high-temperature annealing process by protecting the (Al) GaN surface outside the source/drain electrode, so that the dynamic performance of the device is improved. When the off-state stress of the drain electrode is 600V, N is adopted before high-temperature annealing₂Production of Ga by O plasma treatment₂O₃/Al₂O₃Device with passivation layer (sample A) and using N after high temperature annealing₂Production of Ga by O plasma treatment₂O₃/Al₂O₃The increase in dynamic resistance of the device of the passivation layer (sample B) was 8.6% and 49%, respectively.

Drawings

FIG. 1 is a schematic diagram of a device structure after ohmic contact is made according to an embodiment;

FIG. 2 is Ga formation of example₂O₃/Al₂O₃The device structure schematic diagram after the protective layer;

FIG. 3 is a schematic diagram of a device structure after a gate electrode is formed according to an embodiment;

FIG. 4 shows the use of N prior to high temperature annealing prepared in example 2₂Production of Ga by O plasma treatment₂O₃/Al₂O₃Device with passivation layer and method of using N after high temperature annealing₂Production of Ga by O plasma treatment₂O₃/Al₂O₃The relationship curve of the increase of the dynamic resistance of the device of the passivation layer and the off-state stress of the drain electrode;

in the figure, AlGaN/GaN epitaxy 1, source-drain electrode 2, Ga₂O₃/Al₂O₃A protective layer 3, a gate electrode 4.

Detailed Description

The following is a further description of the embodiments of the present invention with reference to the examples, but the invention is not limited thereto. It is noted that the processes described below, if not specifically described in detail, are all realizable or understandable by those skilled in the art with reference to the prior art. The reagents or apparatus used are not indicated to the manufacturer, and are considered to be conventional products available by commercial purchase.

Example 1

This example provides a solution of Ga₂O₃/Al₂O₃The HEMT device of the protective layer comprises AlGaN/GaN epitaxy 1, two ends of the upper surface of the AlGaN/GaN epitaxy are respectively connected with a source drain electrode 2, the source drain electrode adopts a method of combining electron beam evaporation and magnetron sputtering, and the whole wafer is subjected to N before the source drain electrode is subjected to high-temperature annealing (more than 800 ℃), as shown in figure 3₂O plasma treatment to form Ga₂O₃/Al₂O₃And after the protective layer 3, performing a high-temperature annealing process, wherein a gate electrode 4 is arranged on the source electrode side of the source drain electrode.

Said has Ga₂O₃/Al₂O₃The HEMT device of the protective layer comprises AlGaN/GaN epitaxy 1, source and drain electrodes 2 and Ga₂O₃/Al₂O₃A protective layer 3 and a gate electrode 4; two ends of the upper surface of the AlGaN/GaN epitaxy 1 are respectively connected with a source drain electrode 2; the Ga is₂O₃/Al₂O₃The protective layer 3 is laminated on the AlGaN/GaN epitaxial layer 1; the gate electrode 4 is arranged at Ga₂O₃/Al₂O₃On the protective layer.

The present example also provides a method of preparing the organic compound having Ga₂O₃/Al₂O₃A method of protecting a HEMT device comprising the steps of:

(1) defining a source and drain electrode area after mesa isolation, then depositing a source and drain electrode 2 on the upper surface of the AlGaN/GaN epitaxy 1, wherein the adopted source and drain electrode structure is TiAlNiTi (20/100/10/100 nm), TiAl is obtained by electron beam evaporation, NiTi is obtained by magnetron sputtering, and after metal stripping, NiTi obtained by magnetron sputtering completely wraps TiAl obtained by the following electron beam evaporation, as shown in figure 1;

(2) after the source/drain electrode is stripped, N is performed₂O plasma treatment, N₂The flow rate of O is 87 sccm, the power is 200W, the pressure of the cavity is 600 mTorr, the temperature is 250 ℃, and the processing time is 20 min; formed Ga₂O₃/Al₂O₃The thickness of the protective layer 3 is 3 nm, as shown in fig. 2;

（3）N₂after the O plasma treatment, a high-temperature annealing process is carried out, wherein the annealing temperature is 830 ℃, and N is₂Atmosphere, annealing time is 1 min; finally, defining the gate region, depositing a gate electrode 4NiAu (50/250 nm), as shown in FIG. 3, to obtain the gate electrode with Ga₂O₃/Al₂O₃A HEMT device of the protective layer.

Ga prepared in example 1₂O₃/Al₂O₃The HEMT device of the cap layer has a low interface state density and excellent high frequency and dynamic characteristics, as shown in fig. 4.

Example 2

This example provides a solution of Ga₂O₃/Al₂O₃Referring to fig. 3, the HEMT device of the protective layer comprises an AlGaN/GaN epitaxy 1, wherein two ends of the upper surface of the AlGaN/GaN epitaxy are respectively connected with a source drain electrode 2, and the source drain electrode adopts a method of combining electron beam evaporation and magnetron sputtering to perform source drain electrodeN is applied to the whole wafer before the ultra-high temperature annealing (over 800℃)₂O plasma treatment to form Ga₂O₃/Al₂O₃And after the protective layer 3, performing a high-temperature annealing process, wherein a gate electrode 4 is arranged on the source electrode side of the source drain electrode.

Said has Ga₂O₃/Al₂O₃The HEMT device of the protective layer comprises AlGaN/GaN epitaxy 1, source and drain electrodes 2 and Ga₂O₃/Al₂O₃A protective layer 3 and a gate electrode 4; two ends of the upper surface of the AlGaN/GaN epitaxy 1 are respectively connected with a source drain electrode 2; the Ga is₂O₃/Al₂O₃The protective layer 3 is laminated on the AlGaN/GaN epitaxial layer 1; the gate electrode 4 is arranged at Ga₂O₃/Al₂O₃On the protective layer.

The present example also provides a method of preparing the organic compound having Ga₂O₃/Al₂O₃A method of protecting a HEMT device comprising the steps of:

(1) defining a source-drain electrode region after mesa isolation, then depositing a source-drain electrode 2 on the upper surface of the AlGaN/GaN epitaxy 1, wherein the adopted source-drain electrode structure is TiAlNiAuTi (20/100/10/100/100 nm), TiAlNiAu is obtained by electron beam evaporation, the last layer of Ti is obtained by magnetron sputtering, and Ti obtained by magnetron sputtering completely wraps the TiAlNiAu obtained by the electron beam evaporation below after metal stripping, as shown in FIG. 1;

(2) after the source/drain electrode is stripped, N is performed₂O plasma treatment, N₂The flow rate of O is 120 sccm, the power is 250W, the pressure of the cavity is 800 mTorr, the temperature is 250 ℃, and the processing time is 10 min; formed Ga₂O₃/Al₂O₃The thickness of the protective layer 3 is 4 nm, as shown in fig. 2;

（3）N₂after the O plasma treatment, a high-temperature annealing process is carried out, wherein the annealing temperature is 830 ℃, and N is₂Atmosphere, annealing time is 1 min; finally, defining the gate region, depositing a gate electrode 4NiAu (50/250 nm), as shown in FIG. 3, to obtain the gate electrode with Ga₂O₃/Al₂O₃HEMT device of protective layer。

FIG. 4 shows the use of N prior to high temperature annealing prepared in example 2₂Production of Ga by O plasma treatment₂O₃/Al₂O₃Device with passivation layer (sample A) and using N after high temperature annealing₂Production of Ga by O plasma treatment₂O₃/Al₂O₃The increase of the dynamic resistance of the device of the passivation layer (sample B) and the off-state stress relationship curve of the drain electrode, the stress application time is 10s, and the only difference between the two samples is N₂The O plasma treatment process is performed before high-temperature annealing and after high-temperature annealing. It can be seen that the dynamic resistance of both samples increased with increasing drain off stress, but the dynamic resistance of sample B increased more prominently, and that the dynamic resistance of the device of sample a increased only 8.6% with a drain off stress of 600V, compared to 49% for sample a, indicating that Ga was used₂O₃/Al₂O₃The protective layer structure effectively reduces or avoids interface states introduced to an (Al) GaN interface in a high-temperature annealing process by protecting the (Al) GaN surface outside the source/drain electrode, and improves the dynamic performance of the device.

The above embodiments are only preferred embodiments of the present invention, and are not intended to limit the present invention, and the changes, replacements, modifications, etc. made by those skilled in the art without departing from the spirit of the present invention should belong to the protection scope of the present invention.

Claims (3)

1. Has Ga₂O₃/Al₂O₃The HEMT device of the protective layer is characterized by comprising AlGaN/GaN epitaxy, a source drain electrode and Ga₂O₃/Al₂O₃A protective layer and a gate electrode; two ends of the upper surface of the AlGaN/GaN epitaxy are respectively connected with a source drain electrode; the Ga is₂O₃/Al₂O₃The protective layer is laminated on the AlGaN/GaN epitaxy; the gate electrode is arranged at Ga₂O₃/Al₂O₃On the protective layer.

2. Ga according to claim 1₂O₃/Al₂O₃The HEMT device of the protective layer, characterized in that the distance from the gate electrode to the source electrode is smaller than the distance from the gate electrode to the drain electrode.

3. Ga according to claim 1₂O₃/Al₂O₃HEMT device of a protective layer, characterized in that the Ga₂O₃/Al₂O₃The thickness of the protective layer is 3-5 nm.

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