悬浮区熔法生长锗单晶

Germanium Crystal Grown with Floating Zone Method

采用悬浮区熔工艺,生长出了最大直径(等径部分)22 mm的<100>晶向锗单晶,单晶等径长度20 mm,总长度80 mm。为减小锗单晶生长中的重力作用,并提高温度梯度以增强结晶趋动力,特别设计了锗单晶生长用的加热线圈,包括设计线圈的内径为18 mm,线圈的下表面设计为0°的平角,上表面设计成9°的锥形等。改进后的加热线圈有效地减小了熔体的质量,消除了熔体因重力作用而引起的下坠及因下坠而在上界面形成的无法熔化的腰带。实验表明,锗单晶生长对功率变化非常敏感,生长过程中极易引入位错,但在有大量位错的情况下,晶棱能依然保持完好。

The germanium crystal with diameter 22 mm and 20 mm long has been gown. by floating zone （FZ） method. The grown crystal is with 〈100〉 orientation and a total length of 80 mm. As the germanium melt is more than twice as dense as liquid silicon, to decrease the weight effect of the melt and to increase the temperature gradient in the crystal growth process, a new induction coil with a fiat bottom side, a conical upper side of 9° and a hole diameter of 18 mm was built. With this induction coil to grow germanium crystal, the mass of the melt is reduced effectively and the melt sinkage as well as the waistband which is difficult to melt is avoided. The experiment result shows that the crystallization phase boundary is very sensitive to power fluctuations and the dislocation is easy to form. in germanium single crystal growth. However, when large quantities of dislocation exist in the crystal the crystal ridge can still keep clear.