超高真空化學氣相沉積系統成長高品質鍺磊晶層於磷化銦鎵/砷化鎵基板

Abstract

在本校碩士關景文畢業論文<以超高真空化學氣相沉積系統成長鍺磊晶層於磷化銦鎵/砷化鎵基板之研究>中曾提到，由於磷化鎵銦和鍺之間能隙差異，以及兩者間相近的晶格常數，兩材料的結合可設計於p型鍺通道超薄型電晶體，其研究也成功地首次利用超高真空化學氣相沉積系統(UHVCVD)成長鍺磊晶層於磷化銦鎵/砷化鎵基板上，並且針對其鍺磊晶層之表面構型及成長方式和條件做出初步探討。 本論文接續之前本實驗室之研究結果，先從模擬著手判斷此系統應用層面之可行性後，同樣利用超高真空化學氣相沉積系統(UHVCVD)成長高品質鍺磊晶層於磷化銦鎵/砷化鎵基板，針對鍺磊晶層之品質特性以及後續應用做出進一步探討，成長出的鍺磊晶層除了透過穿透式電子顯微鏡(HRTEM)，以及光激螢光光譜分析(PL)來證明鍺磊晶成長層擁有非常好的結晶品質之外，為了更利於之後本材料系統在高速電子遷移率電晶體(HEMT)中的應用，鍺磊晶層及磷化銦鎵/砷化鎵基板接面價電帶能量差(ΔEv)亦經由表面化學電子能譜儀(XPS)測量出，其值為0.63電子伏特。而此鍺和磷化銦鎵/砷化鎵的異質接面結構預計可以應用於p 型的高速電子遷移率電晶體(HEMT)及金氧半場效電晶體(MOSFET)中。

The report by Kuan Chin Wen [ref] revealed that Ge epitaxial film can be grown on In0.51Ga0.49P/GaAs (100) with 6°-offcut toward [110] substrate by ultra-high vacuum chemical vapor deposition (UHVCVD) system for the first time. This successful growth of Ge on In0.51Ga0.49P/GaAs (100) was done due to the similar lattice mismatch. In this report, we further study the characteristics of Ge epitaxial layer by HRTEM, EDS, XPS, etc.. According to the research before, the band alignment between Ge and In0.51Ga0.49P, the structure is most suitable for ultra-thin body MOSFET with Ge p-channel. To prove the theory, the simulation of the structure was done first. Our device structure lends well for further integration with III-V n-channel devices. Once again crystallinity and defect density of our epitaxial Ge films were evaluated by high-resolution transmission electron microscopy (HRTEM). Inter-diffusion between the interface of Ge and In0.51Ga0.49P was also studied by energy dispersive spectrometer (EDS) line scan profile of transmission electron microscopy. The equipment indicates that Ge epitaxy with good quality and low defect density can be achieved. This was further verified by photoluminescence (PL) that indicated direct band gap emission of Ge. Valence band offset of 0.63 eV at Ge/In0.51Ga0.49P was measured from X-ray photoelectron spectrometer (XPS) measurement. The growth of epitaxial Ge on In0.51Ga0.49P layer can be used for high-speed p-channel HEMT and MOSFET.