台阶聚束AlN高温热退火形貌演化研究

聂子凯; 贲建伟; 张恩韬; 马晓宝; 张山丽; 石芝铭; 吕顺鹏; 蒋科; 孙晓娟; 黎大兵

人工晶体学报, 2023, 52 (6): 1016, 网络出版: 2023-08-13

台阶聚束AlN高温热退火形貌演化研究

Evolution of AlN Step Bunching Morphology During High-Temperature Annealing

论文大纲

聂子凯 ^1,2,*贲建伟 ^1,2张恩韬 ^1,2马晓宝 ^1,2张山丽 ^1,2石芝铭 ^1,2吕顺鹏 ^1,2蒋科 ^1,2孙晓娟 ^1,2黎大兵 ^1,2

作者单位

¹ 中国科学院长春光学精密机械与物理研究所, 发光学及应用国家重点实验室, 长春 130033

² 中国科学院大学, 材料科学与光电工程中心, 北京 100049

氮化铝表面形貌高温热退火台阶聚束斜切衬底热刻蚀 AlN surface morphology high-temperature anneal step bunching miscut substrate thermal etch

摘要

本文在具有0.2°至1.0°斜切角的c面蓝宝石衬底上通过金属有机化合物化学气相沉积(MOCVD)生长了台阶聚束表面形貌AlN外延层, 并系统研究了高温退火过程中其表面形貌演化规律, 且基于第一性原理计算揭示了表面形貌演化背后的物理机制。研究发现, 随退火温度逐步升高, AlN外延层台阶边缘首先出现具有六方结构特征的热刻蚀凹坑, 随后在台面上形成边缘规则的多边形凹坑, 其主要原因是AlN表面台阶边缘处Al-N原子对脱附能量(10.72 eV)小于台面处Al-N原子对脱附能量(12.12 eV)。此外, 由于台阶宽度随斜切角增大而变窄, 台面处凹坑在扩张过程中易与台阶边缘处凹坑发生合并形成V形边缘, 斜切角越大台面上凹坑数量越少。本文阐明了不同斜切角蓝宝石衬底上生长的AlN在高温热退火过程中台阶聚束形貌演变机制, 为面内组分调制的AlGaN基高效深紫外LED提供基础。

Abstract

In this article, an AlN epitaxial layer with a step bunching surface morphology was grown on 0.2° to 1.0° offcut angle c-plane sapphire substrates by metal organic chemical vapor deposition (MOCVD), and the evolution regularity of the surface morphology during high-temperature annealing (HTA) was systematically studied. The underlying physical mechanisms were further uncovered through first-principles calculations. It is revealed that as the annealing temperature gradually increase, thermal etching pits with hexagonal structure characteristics first appear on step edges, and then polygonal pits with regular edges formed on the step terraces. The main reason is that the energy of Al-N pairs decomposed from AlN surface at the step-bunching edges (10.72 eV) is smaller than that of Al-N pairs decomposed from the step terraces (12.12 eV), which leads to the phenomenon that the morphology of step edges will change firstly during HTA. In addition, because the width of the step becomes narrower with the increase of the miscut angle, the pits of the step terraces tend to merge with the pits of the step edges during the expansion process to form a V-shaped edge, resulting in step terraces with large miscut angle hardly appearing pits. This study clarifies the evolution mechanism of step-bunching morphology of AlN grown on sapphire substrates with various offcut angles during high-temperature annealing, and provides theoretical support for the preparation of high-quality AlN templates. This template can be used for AlGaN in-plane composition modulation to obtain high-efficiency deep-ultraviolet light-emitting diodes (DUV-LEDs).

参考文献

[1] NAGASAWA Y, HIRANO A. A review of AlGaN-based deep-ultraviolet light-emitting diodes on sapphire［J］. Applied Sciences, 2018, 8(8): 1264.

[2] LI D B, JIANG K, SUN X J, et al. AlGaN photonics: recent advances in materials and ultraviolet devices［J］. Advances in Optics and Photonics, 2018, 10(1): 43-110.

[3] CHEN Y X, BEN J W, XU F J, et al. Review on the progress of AlGaN-based ultraviolet light-emitting diodes［J］. Fundamental Research, 2021, 1(6): 717-734.

[4] LI J C, GAO N, CAI D J, et al. Multiple fields manipulation on nitride material structures in ultraviolet light-emitting diodes［J］. Light: Science & Applications, 2021, 10: 129.

[5] TAKANO T, MINO T, JUN S K, et al. Deep-ultraviolet light-emitting diodes with external quantum efficiency higher than 20% at 275 nm achieved by improving light-extraction efficiency［J］. Applied Physics Express, 2017, 10(3): 031002.

[6] LU H M, CHEN M R, WANG H, et al. Joint evaluation of internal quantum efficiency and light extraction efficiency for AlGaN-based deep ultraviolet LEDs considering optical polarization properties［J］. Journal of Applied Physics, 2020, 128(12): 125703.

[7] CHOI Y H, RYU G H, RYU H Y. Evaluation of the temperature-dependent internal quantum efficiency and the light-extraction efficiency in a GaN-based blue light-emitting diode by using a rate equation model［J］. Journal of the Korean Physical Society, 2016, 69(8): 1286-1289.

[8] YOSHIKAWA A, CHE S B, YAMAGUCHI W, et al. Proposal and achievement of novel structure InNGaN multiple quantum wells consisting of 1 ML and fractional monolayer InN wells inserted in GaN matrix［J］. Applied Physics Letters, 2007, 90(7): 073101.

[9] SHIH Y H, CHANG J Y, SHEU J K, et al. Design of hole-blocking and electron-blocking layers in AlxGa1-xN-based UV light-emitting diodes［J］. IEEE Transactions on Electron Devices, 2016, 63(3): 1141-1147.

[10] WU F, SUN H D, AJIA I A, et al. Significant internal quantum efficiency enhancement of GaN/AlGaN multiple quantum wells emitting at ~350 nm via step quantum well structure design［J］. Journal of Physics D: Applied Physics, 2017, 50(24): 245101.

[11] HAUGHN C R, RUPPER G, WUNDERER T, et al. Highly radiative nature of ultra-thin c-plane Al-rich AlGaN/AlN quantum wells for deep ultraviolet emitters［J］. Applied Physics Letters, 2019, 114(10): 102101.

[12] ZEIMER U, JESCHKE J, MOGILATENKO A, et al. Spatial inhomogeneities in AlxGa1-xN quantum wells induced by the surface morphology of AlN/sapphire templates［J］. Semiconductor Science and Technology, 2015, 30(11): 114008.

[13] BRYAN I, BRYAN Z, MITA S, et al. Surface kinetics in AlN growth: a universal model for the control of surface morphology in III-nitrides［J］. Journal of Crystal Growth, 2016, 438: 81-89.

[14] BRYAN I, BRYAN Z, MITA S, et al. The role of surface kinetics on composition and quality of AlGaN［J］. Journal of Crystal Growth, 2016, 451: 65-71.

[15] HOU M J, QIN Z X, ZHANG L S, et al. Excitonic localization at macrostep edges in AlGaN/AlGaN multiple quantum wells［J］. Superlattices and Microstructures, 2017, 104: 397-401.

[16] SUN Y H, XU F J, XIE N, et al. Controlled bunching approach for achieving high efficiency active region in AlGaN-based deep ultraviolet light-emitting devices with dual-band emission［J］. Applied Physics Letters, 2020, 116(21): 212102.

[17] SUN H D, MITRA S, SUBEDI R C, et al. Unambiguously enhanced ultraviolet luminescence of AlGaN wavy quantum well structures grown on large misoriented sapphire substrate［J］. Advanced Functional Materials, 2019, 29(48): 1905445.

[18] ALBRECHT M, CREMADES A, KRINKE J, et al. Carrier recombination at screw dislocations in n-type AlGaN layers［J］. Physica Status Solidi (b), 1999, 216(1): 409-414.

[19] WONG Y Y, CHANG E Y, YANG T H, et al. The roles of threading dislocations on electrical properties of AlGaN/GaN heterostructure grown by MBE［J］. Journal of the Electrochemical Society, 2010, 157(7): H746.

[20] REMESH N, MOHAN N, KUMAR S, et al. Vertical current transport in AlGaN/GaN HEMTs on silicon: experimental investigation and analytical model［J］. IEEE Transactions on Electron Devices, 2019, 66(1): 613-618.

[21] SHEN X Q, OKUMURA H, MATSUHATA H. Studies of the annihilation mechanism of threading dislocation in AlN films grown on vicinal sapphire (0001) substrates using transmission electron microscopy［J］. Applied Physics Letters, 2005, 87(10): 101910.

[22] SHEN X Q, MATSUHATA H, OKUMURA H. Reduction of the threading dislocation density in GaN films grown on vicinal sapphire (0001) substrates［J］. Applied Physics Letters, 2005, 86(2): 021912.

[23] SHEN X Q, MATSUHATA H, IDE T, et al. Direct measurement of lateral macrostep velocity on an AlN vicinal surface by transmission electron microscopy［J］. Journal of Applied Physics, 2012, 111(10): 103529.

[24] MIYAKE H, LIN C H, TOKORO K, et al. Preparation of high-quality AlN on sapphire by high-temperature face-to-face annealing［J］. Journal of Crystal Growth, 2016, 456: 155-159.

[25] WANG M X, XU F J, WANG J M, et al. The sapphire substrate pretreatment effects on high-temperature annealed AlN templates in deep ultraviolet light emitting diodes［J］. CrystEngComm, 2019, 21(31): 4632-4636.

[26] SUSILO N, HAGEDORN S, JAEGER D, et al. AlGaN-based deep UV LEDs grown on sputtered and high temperature annealed AlN/sapphire［J］. Applied Physics Letters, 2018, 112(4): 041110.

[27] BEN J W, SUN X J, JIA Y P, et al. Defect evolution in AlN templates on PVD-AlN/sapphire substrates by thermal annealing［J］. CrystEngComm, 2018, 20(32): 4623-4629.

[28] FAN Z Y, RONG G, NEWMAN N, et al. Defect annihilation in AlN thin films by ultrahigh temperature processing［J］. Applied Physics Letters, 2000, 76(14): 1839-1841.

[29] XIONG J J, TANG J J, LIANG T, et al. Characterization of crystal lattice constant and dislocation density of crack-free GaN films grown on Si(111)［J］. Applied Surface Science, 2010, 257(4): 1161-1165.

[30] CHIERCHIA R, BTTCHER T, HEINKE H, et al. Microstructure of heteroepitaxial GaN revealed by X-ray diffraction［J］. Journal of Applied Physics, 2003, 93(11): 8918-8925.

[31] KUBALL M, HAYES J M, PRINS A D, et al. Raman scattering studies on single-crystalline bulk AlN under high pressures［J］. Applied Physics Letters, 2001, 78(6): 724-726.

[32] WANG M X, XU F J, XIE N, et al. High-temperature annealing induced evolution of strain in AlN epitaxial films grown on sapphire substrates［J］. Applied Physics Letters, 2019, 114(11): 11210

聂子凯, 贲建伟, 张恩韬, 马晓宝, 张山丽, 石芝铭, 吕顺鹏, 蒋科, 孙晓娟, 黎大兵. 台阶聚束AlN高温热退火形貌演化研究[J]. 人工晶体学报, 2023, 52(6): 1016. NIE Zikai, BEN Jianwei, ZHANG Entao, MA Xiaobao, ZHANG Shanli, SHI Zhiming, LYU Shunpeng, JIANG Ke, SUN Xiaojuan, LI Dabing. Evolution of AlN Step Bunching Morphology During High-Temperature Annealing[J]. Journal of Synthetic Crystals, 2023, 52(6): 1016.

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