Fabrication of GaN-Based Heterostructures with an InAlGaN/AlGaN Composite Barrier

• 来源期刊: 中国物理快报（英文版）
• 关键词: @@
• 年，卷（期）: 2016,（8）
• 页码范围: 127-130
• 页数: 4页
• 语种: 中文
• DOI: 10.1088/0256-307X/33/8/088102

摘要

GaN-based heterostructures with an InAlGaN/AlGaN composite barrier on sapphire (0001) substrates are grown by a low-pressure metal organic chemical vapor deposition system.Compositions of the InAlGaN layer are determined by x-ray photoelectron spectroscopy,structure and crystal quality of the heterostructures are identified by high resolution x-ray diffraction,surface morphology of the samples are examined by an atomic force microscope,and Hall effect and capacitance-voltage measurements are performed at room temperature to evaluate the electrical properties of heterostructures.The Al/In ratio of the InAlGaN layer is 4.43,which indicates that the InAlGaN quaternary layer is nearly lattice-matched to the GaN channel.Capacitance-voltage results show that there is no parasitic channel formed between the InAlGaN layer and the AlGaN layer.Compared with the InAlGaN/GaN heterostructure,the electrical properties of the InAlGaN/AlGaN/GaN heterostructure are improved obviously.Influences of the thickness of the AlGaN layer on the electrical properties of the heterostructures are studied.With the optimal thickness of the AlGaN layer to be 5 nm,the 2DEG mobility,sheet density and the sheet resistance of the sample is 1889.61 cm2/V.s,1.44 × 1013 cm-2 and as low as 201.1 Ω/sq,respectively.