金屬有機分子束磊晶系統成長高銦含量氮化銦鋁薄膜於矽基板之特性研究

Growth and Characterization of In-rich InxAl1-xN Alloys on Si(111) Substrate by RF-MOMBE

以氮化銦為基底之高銦含量氮化物在紅外光區之高效率光電元件中是相當有潛力的材料，主要是氮化銦在近年來被量測出具有高載子遷移率（~3500 cm2/V-s）與約0.65 eV之能隙，若是摻雜鋁或鎵元素，則可調整其光學能隙落於0.65－6.2 eV之間，是相當有潛力的光電材料。然而，由於InN之熱裂解溫度較低（< 600°C）且無適合之基板，因此較難製備出高品質之InN-based薄膜，因此，InN-based薄膜之光電特性一直無法被確認。本研究中利用金屬有機分子束磊晶系統直接沉積高銦含量氮化鋁銦薄膜於矽（111）基板上，實驗中固定V/III流量比、電將功率等因素僅改變基板溫度在460－540°C範圍內，再透過X光繞射分析儀、掃描式電子顯微鏡與穿透式電子顯微鏡等分析設備進行結構分析與探討。由各項結果指出，InrichInAlN薄膜在460°C基板溫度有較佳之結晶品質，並且從TEM結果顯示In-InAlN薄膜可磊晶成長於Si(111)基板上，其磊晶關係為（0002）InAlN //(111)Si、[-2 110]InAlN // [1-1 0]Si與[01-1 0]InAlN // [-1-12]Si。 InN-based materials are a potential material for various devices such as infrared light emitters and high effi ciency optoelectronic device because of it is high mobility and narrow band gap of 0.6-0.8 eV. However, the InN is diffi cult to grow high-crystalline-quality InN owing to its low dissociation temperature and the lack of lattice-matched substrates. In-rich InAlN fi lms were grown directly on Si(111) substrate by RF-MOMBE without any buffer layer. InAlN films were grown at various substrate temperatures in the range of 460-540 °C with TMIn/TMAl ~ 3.3. Structural properties of InAlN ternary alloys were investigated with x-ray diffraction, scanning electron microscopy, transmission electron microscopy(TEM) . The XRD results indicated that In-rich InAlN fi lms grown with the 460 °C has the smallest full width at half maximum value of 108 arcmin for(0002) X-ray rocking curve(XRC) . Also, ross-sectional TEM from InAlN grown on Si(111) at 460 °C shows that the epitaxial fi lm is in direct contact with orientation relationship of InAlN(0002) InAlN //(111) Si、[-2 110]InAlN // [1-1 0]Si 與 [01-1 0]InAlN // [-1-12]Si.