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The Identify of Microdefects in Semi-insulating Gallium Arsenide

Author: ZhangChunLing
Tutor: XuYueSheng
School: Hebei University of Technology
Course: Materials Physics and Chemistry
Keywords: Semi-insulating gallium arsenide Microdefects Dislocation
CLC: TN304
Type: Master's thesis
Year: 2002
Downloads: 256
Quote: 4
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Abstract


Gallium arsenide (GaAs) is an important compound semiconductor material having a high electron mobility, a direct transition type band structure, etc., suitable for manufacturing a high-frequency, high-speed, high temperature, resistance to radiation, and the light emitting device. GaAs substrate directly affects the quality of the performance of the production in the above devices. However, in the production of GaAs single crystal, in the description of the crystal structure parameters, \The practice shows that only pursuant to a parameter preferred the \GaAs single crystal micro-defects also play an important role in production of the device is good or bad. At home and abroad in recent years GaAs workers on GaAs micro defect study, but mostly for a contradiction, and the definition of micro-defects and explain the difference between physical essence. The purpose of this topic in the interaction between reveal the physical substance of the SI-GaAs microdefects, research micro-distribution of defects in the wafer, and dislocation, further study of micro-defects on device performance. There is a strong interaction between the micro-defects and dislocations, so must the dislocation and micro-defects and study at the same time. The subject first to use ultrasound AB corrosion (USAB) shows the pattern of defects in SI-GaAs, then by transmission electron microscopy (TEM), X-ray transmission topography (XRT), fast scanning optical luminescence (PL Mapping) technologies such as the display a pattern analysis, and to identify the causes of these patterns. After a literature survey and experimental research, the SI-GaAs micro-defects point defects cohesion precipitation to micro, small dislocation loops or impurity atoms and intrinsic point defects in the form of the complex exists in GaAs. The size of the micro-defects in microns, difference Φ2 inches and Φ3 inch wafer micro-defect distribution law. The majority of micro-defects dislocation adsorption inlaid dislocation small handful sorption by the dislocation the stripped area located about 20 microns from the dislocation. Ultrasonic AB etching method can be displayed for a mechanical damage of the surface of the wafer, and has a memory effect of the defective display, shows the etch pits are not instances of defects on the original surface of the wafer, but traces of corrosion defects after about 20 microns. Micro-defects can affect the threshold voltage (V th ) of the field effect transistor (MESFET) and transconductance compression (g m ), the density of the micro defect exists a critical value, when it is below this value, the transconductance compression suddenly increased. Therefore, the physical substance of microdefects correct understanding can guide material production and device process.

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