A method of promoting single crystal yield during melt growth of semiconductors by directional solidification

For certain semiconductors with important applications, the existing unseeded bulk directional solidification crystal growth technique from the melt usually results in poor quality multi-crystalline ingots which causes the low yield of the commercial growth process. The multi-grained crystal growth is mainly caused by the large supercool of the melt, which not only results in a large section of ingot solidifying uncontrollably under spontaneous nucleation but also prohibits the ideal growth condition that small single crystal nuclei form at the very tip of the ampoule and grow into large single grains. To promote nucleation under the condition of small supercooling, a method was employed to induce nucleation by mechanical perturbation at a critical time during growth. The technique was applied to the bulk crystal growth process of Cd1−xZnxTe ingots. The comparison between the crystalline quality of the crystals grown with and without the mechanically induced nucleation shows that the yield of single crystalline can been vastly improved with the application of the technique.