Numerical Simulation of the Thermal Stress Field during Vertical Bridgman CdZnTe Single Crystal Growth

Abstract

Numerical Simulation of the Thermal Stress Field during Vertical Bridgman CdZnTe Single Crystal Growth Juncheng Liu and Guodong Zhang School of Materials Science and Engineering, Shandong University of Technology 12 Zhangzhou Road, Zibo, Shandong, 255091, China (Received 10 September 2007) The thermal stress eld of CdZnTe single crystals grown with the vertical Bridgman method was simulated with the thermal elastic nite-element model. The e ects of the growth parameters, the furnace temperature gradient, the crucible descending velocity, and the thickness of the graphite lm plating on the quartz crucible inner wall, on the thermal stress eld were investigated. The stress at the crystal's edge is much larger than that at the crystal's center, and the stress at the crystal's bottom is larger than that at the crystal's top. The maximum stress ` max' appears at the location where the crystal adhere to the crucible's inner wall. When the furnace's temperature gradient was increased from 5 K/cm to 20 K/cm, the stress in the crystal increased a great deal. If no graphite lm was plated on the crucible's inner wall, the stress at the crystal's l edge increased several times while the stress at the crystal's center increased only a little. On the contrary, when the thickness of the graphite lm was increased from 250 m to 500 m, up to a pure graphite crucible, the stress at the crystal's edge decreased a little, while the stress at the crystal's center decreased a lot. In the range of the 0.5 3 mm/h, the crucible's descending velocity had little e ect on the stress. PACS numbers: 81.10.Aj, 81.10.Fq, 81.05.Dz, 61.72.Bb