標題: Control of metamorphic buffer structure and device performance of InxGa1-xAs epitaxial layers fabricated by metal organic chemical vapor deposition
作者: Nguyen, H. Q.
Yu, H. W.
Luc, Q. H.
Tang, Y. Z.
Phan, V. T. H.
Hsu, C. H.
Chang, E. Y.
Tseng, Y. C.
材料科學與工程學系
電子工程學系及電子研究所
Department of Materials Science and Engineering
Department of Electronics Engineering and Institute of Electronics
關鍵字: InGaAs;strain relaxation;step-graded buffer;MOSCAP;interface trap
公開日期: 5-十二月-2014
摘要: Using a step-graded (SG) buffer structure via metal-organic chemical vapor deposition, we demonstrate a high suitability of In0.5Ga0.5As epitaxial layers on a GaAs substrate for electronic device application. Taking advantage of the technique\'s precise control, we were able to increase the number of SG layers to achieve a fairly low dislocation density (similar to 10(6)cm(-2)), while keeping each individual SG layer slightly exceeding the critical thickness (similar to 80 nm) for strain relaxation. This met the demanded but contradictory requirements, and even offered excellent scalability by lowering the whole buffer structure down to 2.3 mu m. This scalability overwhelmingly excels the forefront studies. The effects of the SG misfit strain on the crystal quality and surface morphology of In0.5Ga0.5As epitaxial layers were carefully investigated, and were correlated to threading dislocation (TD) blocking mechanisms. From microstructural analyses, TDs can be blocked effectively through self-annihilation reactions, or hindered randomly by misfit dislocation mechanisms. Growth conditions for avoiding phase separation were also explored and identified. The buffer-improved, high-quality In0.5Ga0.5As epitaxial layers enabled a high-performance, metal-oxide-semiconductor capacitor on a GaAs substrate. The devices displayed remarkable capacitance-voltage responses with small frequency dispersion. A promising interface trap density of 3 x 10(12) eV(-1) cm(-2) in a conductance test was also obtained. These electrical performances are competitive to those using lattice-coherent but pricey InGaAs/InP systems.
URI: http://dx.doi.org/10.1088/0957-4484/25/48/485205
http://hdl.handle.net/11536/123862
ISSN: 0957-4484
DOI: 10.1088/0957-4484/25/48/485205
期刊: NANOTECHNOLOGY
Volume: 25
Issue: 48
顯示於類別:期刊論文


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