{"title":"设计非线性分级 InAlAs 变质缓冲层,有效降低错位密度","authors":"M.Yu. Chernov, N.D. Prasolov, S.V. Ivanov, V.A. Solov'ev","doi":"10.1016/j.jcrysgro.2024.127702","DOIUrl":null,"url":null,"abstract":"<div><p>Metamorphic In<sub>x</sub>Al<sub>1-x</sub>As (<em>x</em><sub>max</sub> > 0.75) buffer layer (MBL) grown on GaAs with an optimized non-linear graded composition profile along the growth direction is proposed for enhanced reduction of misfit dislocation (MD) density in highly mismatched III-V/GaAs metamorphic heterostructures. The equilibrium distributions of MD density throughout such In<sub>x</sub>Al<sub>1-x</sub>As/GaAs MBLs are calculated. The influence of the initial composition (<em>x</em><sub>min</sub>) of MBL and the elastically strained thin GaAs layer embedded into the In<sub>x</sub>Al<sub>1-x</sub>As MBL on the MD density distribution was studied. An optimum value of the inverse step (Δ), representing the difference between the top In content of the In<sub>x</sub>Al<sub>1-x</sub>As MBL and that of a In<sub>0.75</sub>Al<sub>0.25</sub>As virtual substrate (VS) grown atop is determined. It was theoretically shown that Δ above 0.04 results in relaxation of the elastic stresses in VS via formation of the MDs, while the lower Δ values allow growing the VS completely free of MDs. Finally, the metamorphic In<sub>0.75</sub>Al<sub>0.25</sub>As/graded-InAlAs/GaAs heterostructures differing from each other by only the composition profile of the graded-InAlAs MBL were grown by MBE on GaAs<!--> <!-->(0<!--> <!-->0<!--> <!-->1) and studied by atomic force microscopy. The structure with proposed optimized non-linear graded (<em>x</em> = 0.05–0.77) MBL demonstrated the ∼ 1.5 times less MD density as compared to that with the convex-graded (<em>x =</em> 0.05–0.81) MBL, which was estimated to be at the level of ∼ 2·10<sup>7</sup> cm<sup>−2</sup>.</p></div>","PeriodicalId":353,"journal":{"name":"Journal of Crystal Growth","volume":null,"pages":null},"PeriodicalIF":1.7000,"publicationDate":"2024-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Design engineering of non-linear graded InAlAs metamorphic buffer layers for efficient reduction of misfit dislocation density\",\"authors\":\"M.Yu. Chernov, N.D. Prasolov, S.V. Ivanov, V.A. Solov'ev\",\"doi\":\"10.1016/j.jcrysgro.2024.127702\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Metamorphic In<sub>x</sub>Al<sub>1-x</sub>As (<em>x</em><sub>max</sub> > 0.75) buffer layer (MBL) grown on GaAs with an optimized non-linear graded composition profile along the growth direction is proposed for enhanced reduction of misfit dislocation (MD) density in highly mismatched III-V/GaAs metamorphic heterostructures. The equilibrium distributions of MD density throughout such In<sub>x</sub>Al<sub>1-x</sub>As/GaAs MBLs are calculated. The influence of the initial composition (<em>x</em><sub>min</sub>) of MBL and the elastically strained thin GaAs layer embedded into the In<sub>x</sub>Al<sub>1-x</sub>As MBL on the MD density distribution was studied. An optimum value of the inverse step (Δ), representing the difference between the top In content of the In<sub>x</sub>Al<sub>1-x</sub>As MBL and that of a In<sub>0.75</sub>Al<sub>0.25</sub>As virtual substrate (VS) grown atop is determined. It was theoretically shown that Δ above 0.04 results in relaxation of the elastic stresses in VS via formation of the MDs, while the lower Δ values allow growing the VS completely free of MDs. Finally, the metamorphic In<sub>0.75</sub>Al<sub>0.25</sub>As/graded-InAlAs/GaAs heterostructures differing from each other by only the composition profile of the graded-InAlAs MBL were grown by MBE on GaAs<!--> <!-->(0<!--> <!-->0<!--> <!-->1) and studied by atomic force microscopy. The structure with proposed optimized non-linear graded (<em>x</em> = 0.05–0.77) MBL demonstrated the ∼ 1.5 times less MD density as compared to that with the convex-graded (<em>x =</em> 0.05–0.81) MBL, which was estimated to be at the level of ∼ 2·10<sup>7</sup> cm<sup>−2</sup>.</p></div>\",\"PeriodicalId\":353,\"journal\":{\"name\":\"Journal of Crystal Growth\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":1.7000,\"publicationDate\":\"2024-04-12\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Crystal Growth\",\"FirstCategoryId\":\"88\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0022024824001374\",\"RegionNum\":4,\"RegionCategory\":\"材料科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"CRYSTALLOGRAPHY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Crystal Growth","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0022024824001374","RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"CRYSTALLOGRAPHY","Score":null,"Total":0}
Design engineering of non-linear graded InAlAs metamorphic buffer layers for efficient reduction of misfit dislocation density
Metamorphic InxAl1-xAs (xmax > 0.75) buffer layer (MBL) grown on GaAs with an optimized non-linear graded composition profile along the growth direction is proposed for enhanced reduction of misfit dislocation (MD) density in highly mismatched III-V/GaAs metamorphic heterostructures. The equilibrium distributions of MD density throughout such InxAl1-xAs/GaAs MBLs are calculated. The influence of the initial composition (xmin) of MBL and the elastically strained thin GaAs layer embedded into the InxAl1-xAs MBL on the MD density distribution was studied. An optimum value of the inverse step (Δ), representing the difference between the top In content of the InxAl1-xAs MBL and that of a In0.75Al0.25As virtual substrate (VS) grown atop is determined. It was theoretically shown that Δ above 0.04 results in relaxation of the elastic stresses in VS via formation of the MDs, while the lower Δ values allow growing the VS completely free of MDs. Finally, the metamorphic In0.75Al0.25As/graded-InAlAs/GaAs heterostructures differing from each other by only the composition profile of the graded-InAlAs MBL were grown by MBE on GaAs (0 0 1) and studied by atomic force microscopy. The structure with proposed optimized non-linear graded (x = 0.05–0.77) MBL demonstrated the ∼ 1.5 times less MD density as compared to that with the convex-graded (x = 0.05–0.81) MBL, which was estimated to be at the level of ∼ 2·107 cm−2.
期刊介绍:
The journal offers a common reference and publication source for workers engaged in research on the experimental and theoretical aspects of crystal growth and its applications, e.g. in devices. Experimental and theoretical contributions are published in the following fields: theory of nucleation and growth, molecular kinetics and transport phenomena, crystallization in viscous media such as polymers and glasses; crystal growth of metals, minerals, semiconductors, superconductors, magnetics, inorganic, organic and biological substances in bulk or as thin films; molecular beam epitaxy, chemical vapor deposition, growth of III-V and II-VI and other semiconductors; characterization of single crystals by physical and chemical methods; apparatus, instrumentation and techniques for crystal growth, and purification methods; multilayer heterostructures and their characterisation with an emphasis on crystal growth and epitaxial aspects of electronic materials. A special feature of the journal is the periodic inclusion of proceedings of symposia and conferences on relevant aspects of crystal growth.