Preparition Of Large Diameter Indium Phosphide Single Crystal And Study Of Its Semi-insulating Characteristics

Indium Phosphide (InP) has been indispensable to both optical and electronic devices. This paper used a direct P-injection synthesis and LEC crystal growth method to prepare high purity and various melt stoichiometry conditions polycrystalline InP and to grow high quality, large diameter InP single crystal in our homemade pullers. In this work, we have obtained the following results:1. The synthesis of InP polycrystalline has been deeply analysed. It is the first time to use double-tube injector on the world. By optimizing the thermal field and other parameters, it can be achieved to synthesize 4 to 6 kilograms polycrystalline InP of high purity in 60 to 90 minutes. The InP melt of different stoichiometric- ratio such as In-rich and P-rich has been obtained by means of adjusting the weights of indium and red phosphorus, and it established the base of the study of the different stoichiometric ratios on the characteristics of InP.2. By use of the results of the research work of twinnings and dislocations, the conditions of the thermal field and the process parameters has been modulated. The maximum diameter of single crystal could be reached to 5.5 inch and the maximum length of the semi-insulating single crystal was 190mm.3. The in-situ P injection method was used to synthesize and the LEC method was used to pull the different stoichiometric-ratio InP single crystals. It has been tested that, the carrier concentration of InP materials pulled from P-rich melts is about 1-2×10¹⁵cm^-3 higher than that from In-rich melts. It is proved that there has been a relative high concentration of VInH4 in the InP materials pulled by the LEC method. The concentration of VInH4 is highest in the P-rich melts and lowest in the In-rich ones.4. Through a comprehensive study of the deep level defects in the Fe-doped and undoped annealed InP wafers, it has been confirmed clearly that the Fe-doped semi-insulating InP one has higher concentration of deep level defects which participate in the electrics compensation so that the electrics performance is reduced, however, there is lower concentration of deep level defects in the undoped annealed InP and the deep level defects are restrained so that the electrics compensation can be ensured. The electrics performance, thermal stability, homogeneity and so on are closely related to the deep level defects in the materials. The approaches to restrain the defects and improve the quality of the materials were given by analyzing the rules of deep level defects and the relationship between heat treatments and growing conditions.