MOCVD反應器氮化鎵薄膜成長之三維熱流場分析研究

Abstract

使用金屬有機物化學氣相沉積(MOCVD)磊晶方式研製發光二極體的氮化鎵(GaN)發光層薄膜之製程品質優良與否取決於反應器(reactor)內部流場穩定性、溫度控制與反應氣體的導入方式…等因素，各因子對沉積物之均勻性(uniformity)影響重大。反應器的設計會影響腔體內部流場之穩定性。以低壓腔體磊晶技術為主的反應器，面臨問題包括：低壓環境中，薄膜沉積速度慢；加熱與氣流場均勻性不佳，易造成薄膜脆裂或缺陷增加；升降溫控制不佳，在降溫過程太快而造成產生薄膜缺陷。 本研究針對GaN薄膜成長於矽基板時，探討反應腔內部之熱流場對薄膜沉積均勻性的影響，並使用三維模型進行模擬，以求模擬環境能盡量接近反應器實際運作的內部熱流場環境，模擬結果所得之經驗模式能具備參考價值，作為MOCVD系統參數之依據。

The quality of GaN thin film in terms of the uniformity of the deposition in MOCVD method is determined by the flow uniformity, flow stability, temperature control, the gas mixture, and chemical reaction introduced in the reactor. Some critical problems of MOCVD to be solved including the rate of film deposition is low,the yield of the deposition is not remarkable, unsatisfactory temperature control caused cracks on the epi-layers. This research discussed that the thermal flow effects the uniformity of Si-based GaN film in MOCVD reactor.To obtain the opimal parameter of MOCVD system,this study compared the three-dimensional simulation results with the experimental data.