Investigation On Defects And Electrical Properties Of Ion-Implanted Large Diameter SI-GaAs

In recent years, with the rapid development of micro-electronics and photoelectron technology, especially due to the increase of the markets of GaAsIC, it is very necessary to improve the quality of semi-insulating GaAs (SI-GaAs) substrate and the ion implantation technology to match the needs of the market. Ion-implanted large diameter SI-GaAs is widely applied to creating micro-electronics and photoelectron devices. The intrinsic quality of SI-GaAs has a direct influence on the results of electrical activation, so the investigation of defects , the effects of ion implantation on defects and the electrical properties of large diameter SI-GaAs is very important.In this paper, the distribution, pattern and density of detects in 6-inch as-grown SI-GaAs and Si+-implanted SI-GaAs have been investigated by means of ultrasonic AB etching and microscopy observation, etc. The radial distribution of EL2 concentration was obtained using FTIR technique in detail. The electrical properties were measured by Hall system, and the electrical activity of different conditions was compared. The mechanics of ion implantation effects on defects and the electrical parameters was also investigated.The experimental results show that there are cell and netted structures of dislocation in the sample surface, and so on. The distribution of dislocation density is W shape on sample diameter. The distribution of EL2 concentration is relatively lower in the center and higher on the edge of the wafer along the radial direction of as-grown samples. A large number of As precipitates have been found following Si+ implantation, which are due to the As precipitates of as-grown samples and the out-diffusion of As interstitial atoms. The radial distribution of electrical parameters has also been investigated. The radial distribution of the resistivety of as-grown samples is U-shape, mobility is W-shape, and carrier concentration shows M-shape. It is not larger change of the radial distribution of electrical parameters under the different conditions. However, the electrical activity and uniformity of electrical parameters radial distributing are improved evidently due to the well-even redistribution of the EL2 of the Si+-implanted GaAs at As+ co-implantation.