论文部分内容阅读
本文从4英寸无位错锗单晶的生长温度梯度条件出发,设计开发了直拉法生长4英寸无位错锗单晶的双加热器热场系统;并对其热场进行了一系列的数值模拟研究,获得了4英寸无位错锗单晶的温度分布、轴向和径向的温度梯度分布以及热应力的分布结果:双加热器热场系统生长的锗单晶中轴向温度梯度在0.1-0.6 K·cm-1范围内,径向温度梯度为0.02-0.26 K·cm-1;锗单晶中局部区域的热应力值超过了锗单晶的临界切应力1 MPa,其他区域的热应力小于临界切应力。实验将双加热器热场系统中生长的无位错锗单晶,按要求切取测试片后进行位错腐蚀测量研究,获得测试片的位错密度和锗晶体的位错纵向分布。论文研究结果表明,锗单晶晶体中的应力分布数值模拟预期结果与实验生长的锗单晶位错腐蚀实验研究结果一致:该双加热器热场系统适合拉制4英寸无位错锗单晶;其位错呈离散分布,位错密度为350-480 cm-2。
Based on the growth temperature gradient of 4-inch dislocation-free germanium single crystal, this paper designed and developed a two-heater thermal field system by Czochralski method to grow 4-inch single crystal without dislocation germanium. A series of Numerical simulation results show that the temperature distribution, temperature gradient distribution and thermal stress distribution of 4-inch dislocation-free germanium single crystal are obtained. Results: The axial temperature gradient of the germanium single crystal grown by the double-heater thermal field system In the range of 0.1-0.6 K · cm-1, the radial temperature gradient is 0.02-0.26 K · cm-1. The thermal stress in the local region of germanium single crystal exceeds the critical shear stress of germanium single crystal by 1 MPa, and the other regions The thermal stress is less than the critical shear stress. In the experiment, a dislocation-free germanium single crystal grown in a double-heater thermal field system was cut out to measure the dislocation corrosion after the test piece was cut as required to obtain the dislocation density of the test piece and the longitudinal dislocation distribution of the germanium crystal. The results show that the expected results of the numerical simulation of stress distribution in germanium single crystal are in agreement with experimental results of single crystal dislocation corrosion of germanium. The double-heater thermal field system is suitable for drawing 4-inch single crystal without dislocations The dislocations are distributed discretely with a dislocation density of 350-480 cm-2.