Method of in-situ depositing high dielectric constant Al2O3 and metal film on GaAs substrate

Abstract

This invention discloses a method for in-situ depositing high dielectric constant Al203 and a metallic film, which uses EB vacuum evaporation, takes pure Al203particles and a metal as the evaporation source materials to finish the film evaporation and deposition including: cleaning a chip of the GaAs basic material, photoetching patterns on the cleaned GaAs chip, putting the chip in an EB reaction chamber to be vacuum-pumped to get a pre-designed value and activating the GaAs chip surface with Ar ions, then setting density D and coefficient Z of the source materials, setting the high voltage at 10Kv to be added with different evaporation currents carrying out the evaporation and deposition of the film and the metallic film to reduce the current to zero quickly when the thickness reaches to the required value and to strip off the metal evaporated on the chip.

Description

technical field [0001] The invention belongs to the technical field of microelectronics, and relates to compound processing in device manufacturing, in particular to an in-situ deposition of high dielectric constant Al on a GaAs base. 2 o 3 and metal film methods for mass production of GaAs-based devices and ICs. Background technique [0002] With the requirement for high speed, the size of the device keeps shrinking, which brings about a corresponding reduction in the thickness of the gate oxide layer. However, when the thickness of the gate oxide layer is less than 20 Ȧ, a significant quantum tunneling effect will be caused, resulting in a gate leakage current that affects device performance. In the case of the same equivalent thickness of the gate dielectric, if a high κ material is used instead of SiO 2 As a gate dielectric, it can significantly reduce the gate leakage current caused by direct tunneling. [0003] Among many high dielectric constant κ materials, Al 2...

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Problems solved by technology

[0028] 1) Cannot form mass production;

[0029] 2) Generated Al 2 o 3 Film thickness cannot be precisely controlled;

[0030] 3) The thickness uniformity of each part in the sheet and the thickness repeatability between sheets are poor;

[0031] 4) Al generated due to anodic oxidation 2 o 3 The composition thickness is not uniform, and the aluminum side is rich in Al +3 The ion membrane, the oxygen-rich ion membrane is on the side of the electrolyte, and the insulating Al is in the middle. 2 o 3 layer, so the film behaves as a PIN structure, which makes it have rectification characteristics, which is very unfavorable in application

[0059] The above two processes require many steps, so the work efficiency is low and the production cost is high. In addition to an EB evaporation table, a DC reactive sputtering table of hundreds of thousands to more than 1 million yuan is required, and dozens of At the same time, due to the existence of harmful gases in the etching, it not only causes harmful pollution to the environment, but also, the film is exposed to the atmosphere eight times during the processing process, which affects the characteristics of the device, especially the stability and quality of the device. Reliability and yield will have a great impact; in addition, use DC reactive sputtering equipment to deposit Al 2 o 3 A large amount of very expensive high-purity gas, such as high-purity Ar, is required, and Al 2 o 3 The deposition uniformity and repeatability are not very good, the deposition rate and film thickness cannot be directly monitored, and the purpose of precise control cannot be achieved

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