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篇名 金屬有機前驅物-三甲基銦對氮化銦磊晶薄膜之光電及化學特性影響
卷期 207
並列篇名 Investigation of Trimethylindium Flow Rate on Electro-Optical and Chemical Properties of InN Epilayer Grown on GaN/Al2O3 Substrate
作者 陳維鈞郭守義賴芳儀蕭健男
頁次 055-070
出刊日期 201606

中文摘要

III-V 族化合物半導體是目前發光二極體元件的主要材料,其中氮化銦具有許多優異光電特性,其窄光學 能隙 (0.65 eV) 是 III-V 族氮化物材料延伸至紅外光區的重要特性之一。由於大多數的氮化銦都是以金屬有 機化學氣相沉積製備,然而金屬有機前驅物 (三甲基或三乙基) 中含碳氫氧等元素,使得材料在成長過程 中造成元素的摻雜而影響了其光電特性,因此本研究以三甲基銦為三族前驅物,並以金屬有機分子束磊晶 系統成長氮化銦薄膜,同時進行其化學組態、雜質元素與光電特性之相關性分析,以了解金屬有機前驅物 對成長氮化物之影響。由二次離子質譜儀與 X 光光電子光譜儀結果發現,前驅物三甲基銦中的碳與氫會 隨著製程中摻入 InN 薄膜,其濃度會隨著三甲基銦流量增加而增加。相反地,薄膜中的氧含量會隨著三甲 基銦增加而減少。並且在 InN 表面有高濃度的碳、氫與氧雜質,因此當表面經過 HCl 蝕刻後,V/III~1.81 所成長之 InN 薄膜的電子濃度由 5.57  1019 cm3 降至 3.31  1019 cm3、遷移率則由 192 cm2/V-s 提升至 335 cm2/V-s。光學性質部分透過光激發螢光光譜得知,近能帶邊緣放射訊號會隨著 V/III 流量比增加而藍 移是因為 Burstein-Moss effect,而高電子濃度大部分是氮空缺與雜質元素所貢獻,因此高載子濃度是造成 光學吸收限藍移的主要原因。另外可知,三甲基銦前驅物在製程中會間接提高載子濃度,並影響光電特性。

英文摘要

III-nitride is important material for high power light emitting diode (LED) devices. Specially, InN has attracted the most attention among the III-V nitrides because of its noticeable narrow band gap (0.65 eV), small effective mass and high electron mobility. Due to most InN fi lms were prepared by MOCVD. However, metal-organic precursor often included carbon, hydrogen and oxygen. Therefore, we discussed the chemical and electro-optical properties of InN fi lms grown on MOCVD-GaN lyaer with different trimethylindium fl ow rate. The InN fi lms were characterized by secondary ion mass spectrometry, X-ray photoelectron spectroscopy photoluminescence and Hall effect. InN films were grown on MOCVD-GaN/Al2O3 substrate by plasma-assisted metal-organic molecular beam epitaxy. Secondary ion mass spectrometry and X-ray photoelectron spectroscopy results showed that carbon and hydrogen of trimethylindium precursor were incorporated during InN fi lms growth. Also, the C and H concentrations increase with increasing trimethylindium fl ow rate. On the other hand, the oxygen concentration decreases with increasing trimethylindium flow rate. A relatively high C, H and O concentration exists near the surface of the InN film. Therefore, before etching, the fi lm exhibits the high carrier concentration of 5.57 X 1019 cm-3 and low mobility of 192 cm2/V-s. After etching, the etched InN fi lm exhibited a decreased carrier concentration of 3.31 X 1019 cm-3, increased electron mobility of 335 cm2/V-s. Optical properties showed that the PL spectra exhibited blue-shift with increasing V/III flow ratio due to the Burstein-Moss effect. However, high carrier concentration was measured probably due to nitrogen vacancies and impurity contributed. Therefore, blue shift of the optical absortion is caused by high carrier concentration.

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