雙加熱MOCVD系統成長氮化銦鎵薄膜之磊晶機制研究

Abstract

本論文以雙加熱有機金屬化學氣相沈積系統（two-heater MOCVD reactor）成長氮化銦鎵（InGaN）薄膜，改變成長溫度、上加熱溫度以及成長壓力，研究氮化銦鎵磊晶機制。變成長溫度系列中，雙加熱和傳統系列之氮化鎵成長效率（growth efficiency），因在質傳成長區域（mass-transport region）內而皆不隨溫度改變；氮化銦成長效率則皆以625℃為界成兩段式變化，高溫區隨溫度下降趨勢由阿瑞尼士擬合，所得活化能值分別為0.92 eV 和0.93 eV，推測主要是氮化銦熱分解（decomposition）導致。雙加熱和傳統系列之氮化銦成長效率在高溫區的差值，進一步由變上加熱溫度系列樣品分析成長效率損耗（growth efficiency loss），擬合結果活化能值為1.36 eV，推測由化合物形成聚合物反應（oligomer formation）主導造成。而由變成長壓力系列分析化合物形成聚合物反應影響程度，在一般壓力（200 mbar）下僅約13%以內，不甚嚴重；且在上加熱溫度800℃下，甚至幾乎沒有造成成長效率損耗。

In this thesis, InGaN films grown by two-heater MOCVD reactor with varying growth temperature, ceiling temperature and pressure were used to study indium incorporation behavior in InGaN. The GaN growth efficiencies in InGaN grown by two-heater and conventional reactors both kept at almost constant due to the mass-transport region; while the InN growth efficiencies both started to drop obviously with growth temperature over 625℃, and the activation energies of which obtained from Arrhenius fitting were 0.92 eV and 0.93 eV respectively. We therefore referred the decreasing InN growth efficiency with growth temperature to InN decomposition. From the activation energy of varying ceiling temperature series, 1.36 eV, the deviation of InN growth efficiencies between two-heater and conventional growth may be caused by oligomer formation. However the growth efficiency loss resulted from oligomer formation under typical growth pressure, 200 mbar, was about 13% at the most, which was acceptable and slight. And with the proper ceiling temperature under 800℃, oligomer formation even has no effect on growth efficiency loss.