论文部分内容阅读
一、引言目前用引上法生长半导体晶体,其直径控制往往是靠熟练的操作,他们连续进行小规模地调节以达到半导体熔化温度。这种调节影响了处在固-液界面的半导体熔料结晶速率,因此需对拉单晶直径实行严格的控制。然而,人工控制开环系统不能提供自动化闭环控制系统所能提供的那样晶体直径。以前使用了包括高温计在内的闭环电光系统,即从待拉半导体晶体的弯曲液面部份所发射的(包括反射)光用来产生电控制信
I. INTRODUCTION At present, the growth of semiconductor crystals by the lead-in method, the diameter of which is often controlled by skilled operation, they continue to conduct small-scale adjustments in order to achieve the semiconductor melting temperature. This adjustment affects the crystallization rate of the semiconductor melt at the solid-liquid interface and therefore requires strict control over the diameter of the drawn single crystal. However, manually controlled open-loop systems do not provide the crystal diameter that an automated closed-loop control system can provide. Previously closed-loop electro-optical systems, including pyrometers, were used, that is, emitted (including reflected) light from the curved liquid surface portion of the semiconductor crystal to be pulled to produce an electrical control signal