摘要
Controlling the epitaxial growth mode of semiconductor layers is crucial for optimizing material properties and device performance.In this work,the growth mode ofα-Ga_(2)O_(3) heteroepitaxial layers was modulated by tuning miscut angles(θ)from 0°to 7°off the(1010)direction of sapphire(0002)substrate.On flat sapphire surfaces,the growth undergoes a typical three-dimensional(3D)growth mode due to the random nucleation on wide substrate terraces,as evidenced by the hillock morphology and high dislocation densities.As the miscut angle increases toθ=5°,the terrace width of sapphire substrate is comparable to the distance between neighboring nuclei,and consequently,the nucleation is guided by terrace edges,which energetically facilitates the growth mode transition into the desirable two-dimensional(2D)coherent growth.Consequently,the mean surface roughness decreases to only 0.62 nm,accompanied by a significant reduction in screw and edge dislocations to 0.16×10^(7) cm^(-2)and 3.58×10^(9) cm^(-2),respectively.However,the further increment of miscut angles toθ=7°shrink the terrace width less than nucleation distance,and the step-bunching growth mode is dominant.In this circumstance,the misfit strain is released in the initial growth stage,resulting in surface morphology degradation and increased dislocation densities.
作者
郝景刚
张彦芳
张贻俊
徐科
韩根全
叶建东
Jinggang Hao;Yanfang Zhang;Yijun Zhang;Ke Xu;Genquan Han;Jiandong Ye(Test&Analysis Platform,Suzhou Institute of Nano-Tech and Nano-Bionics,Chinese Academy of Sciences,Suzhou 215123,China;School of Electronic Science and Engineering,Nanjing University,Nanjing 210023,China;Wuxi Institute of Technology,Wuxi 214121,China;School of Microelectronics,Xidian University,Xi'an 710071,China;Suzhou National Laboratory for Materials Science,Jiangsu Institute of Advanced Semiconductors,Suzhou 215123,China)
基金
Project supported by the National Key Research and Development Program of China (Grant No.2022YFB3605403)
the National Natural Science Foundation of China (Grant Nos.62234007,62241407,62293521,62304238,62241407,U21A20503,and U21A2071)
the Key-Area Research and Development Program of Guangdong Province,China (Grant No.2020B010174002)
the Cultivation Project for Youth Teachers in Jiangsu Province
Jiangsu Funding Program for Excellent Postdoctoral Talent。
