Inhibition method for depositing Al2O3 interface transition layer on AlGaN material surface

Abstract

The invention discloses a method for restraining the deposition of an Al2O3 interface transition layer on an AlGaN material surface, which comprises the following steps: carrying out the organic ultrasonic cleaning to a base-plate which is deposited with an AlGaN epitaxial layer, washing and drying by floating deionized water, corroding for 20-40s through arranging solution with the composition of HCl:HF:H2O=1:1:8, and washing and drying the corroded base-plate by the floating deionized water, adjusting the power of an upper electrode on an inductive coupling plasma dry etching machine to be 200-400W, and the power of a lower electrode to be10-30W, instantly arranging the dried base-plate into a reaction chamber of the etching machine, and adjusting the N2 flow capacity of the reaction chamber to be 5-15sccm and the pressure to be 1-2Pa, and carrying out the surface preparation to the plasma body, then instantly arranging the base-plate in a reaction chamber of an atom layer depositing device, and carrying out the subsequent Al2O3 medium depositing technique. The invention has the advantages of simple technique, easy to carry out, and the method can restrain the deposition of the Al2O3 interface transition layer on the AlGaN material surface, and can improve the breakdown voltage of an AlGaN / GaN MISHEMT device and the service life.

Description

technical field [0001] The invention belongs to the technical field of microelectronics, and relates to a manufacturing process of a compound semiconductor metal-insulating layer-semiconductor field effect transistor, specifically a transition layer between an insulating medium and a semiconductor layer of a compound semiconductor metal-insulating layer-semiconductor field effect transistor control method. Background technique [0002] The third-generation wide bandgap semiconductor represented by gallium nitride GaN has excellent characteristics such as large bandgap width, high critical field strength, high thermal conductivity, high carrier saturation rate, and high concentration of two-dimensional electron gas at the heterojunction interface. make it attract people's attention. In particular, the metal Schottky field effect transistor MESFET and AlGaN / GaN heterojunction metal-insulator-semiconductor high electron mobility transistor MISHEMT devices made of this material...

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Problems solved by technology

[0004] However, it was found in the research that the AlGaN epitaxial layer is easy to form a natural oxide layer, so the surface must be properly treated before the device is prepared, but it is difficult to obtain an atomically clean surface only by ultrasonic cleaning of an organic solution. After the AlGaN epitaxial layer was ultrasonically cleaned with an organic solution, the nanoscale thickness of Al was directly deposited by ALD. 2 o 3 When the insulating medium is used, it is inevitable to combine the AlGaN epitaxial layer with Al 2 o 3 A transition layer is formed at the interface of the insulating film, and the quality of the transition layer is relatively loose, causing Al 2 o 3 The degradation of the film insulation performance and the decrease of the dielectric constant will eventually lead to an increase in device gate leakage current, a decrease in breakdown voltage, a degradation in device performance, and a greatly reduced lifespan. 2 o 3 Effective control of the transition layer at the thin-film interface is the primary issue in the development of high-performance AlGaN / GaN MISHEMT devices, but so far there has been no public report

In 2005, Hong Liang Lu deposited Al on GaAs substrate 2 o 3 In the case of medium, it was found that the GaAs substrate was placed in the PECVD reaction chamber and heated to 300°C before deposition and 3 Plasma treated the surface of GaAs material for 4 minutes, and then deposited 3.2nm thick Al by ALD method 2 o 3 Thin films, found in GaAs and Al by high-resolution transmission electron microscope HRTEM observation 2 o 3 There is almost no transition layer at the interface of the film, that is, the transition layer is well suppressed, and only deposited Al 2 o 3 Compared with the GaAs material etched by HF before the film, the high-frequency C-V test results also show that the MOS capacitor prepared by the former is higher than the latter, indicating that the former has better interface characteristics, but this method is only used for GaAs materials and cannot be used directly. For AlGaN materials and Al 2 o 3 Effective suppression of interfacial transition layers

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