準分子雷射退火矽膜之凝固速率研究與分析

Solidification Velocity in Polycrystalline Silicon Thin Films during Excimer Laser Crystallization

郭啟全(Chil-Chyuan Kuo)

《建國科大學報》 27卷4期 (2008/07) Pp. 13-29

https://doi.org/10.6995/JCTU.200807.0013

摘要

運用準分子雷射結晶技術(excimer laser crystallization, ELC)來製作低溫多晶矽(low-temperature polycrystalline silicon, LTPS)已經成為主流。由於矽膜相變化過程將影響多晶矽之晶粒大小與結晶品質，因此本研究建構一套具奈秒時間解析(time-resolved)之原位(in-situ)線上光學檢測系統來檢測矽膜經準分子雷射照前後矽膜相變化過程，並藉由所量測之波形來計算液態矽之矽膜表面平均凝固速率(solidification velocity)。研究結果顯示，矽膜表面之液態矽之平均凝固速率於矽膜部分熔化與矽膜全部熔化區域是不同。於矽膜部分熔化區域，矽膜表面之液態矽之平均凝固速率隨著準分子雷射能量增加而減緩。於矽膜全部分熔化區域，矽膜表面之液態矽之平均凝固速率顯著增加，主要原因為液態矽處於極大過冷度。

關鍵字

凝固速率 ； 準分子雷射退火 ； 矽膜

並列摘要

Excimer laser crystallization (ELC) is commonly employed to fabricate low-temperature polycrystalline silicon. A time-resolved in-situ optical system with nanosecond response time is developed to monitor and record the phase transformation process during ELC. The average solidification velocity of liquid silicon (liquid Si) is investigated from the optical spectra recorded by a fast oscilloscope. It is found that the average solidification velocities of liquid Si in the partial-melting and complete-melting regimes are fundamentally different. In the partial-melting regime, the average solidification velocity decreases with increasing excimer laser energy density; while in the complete-melting regime, it increases abruptly due to the presence of deeply supercooled liquid Si.

並列關鍵字

Solidification velocity ； Excimer laser crystallization ； Silicon thin films