Crack-free GaN deposition on Si substrate with temperature-graded AlN buffer growth and the emission characteristics of overgrown InGaN/GaN quantum wells

• Published in: Journal of crystal growth 2014-06, Vol.396, p.1-6
• Main Authors: Chen, Chih-Yen, Chang, Wen-Ming, Chung, Wei-Lun, Hsieh, Chieh, Liao, Che-Hao, Ting, Shao-Ying, Chen, Kuan-Yu, Kiang, Yean-Woei, Yang, C.C., Su, Wei-Siang, Cheng, Yung-Chen
• Format: Article
• Language: English
• Subjects: A1. Nanostructures; A3. Metalorganic chemical vapor deposition; Aluminum nitride; B1. Nitrides; B2. Semiconducting III–V materials; Buffers; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Crack propagation; Cross-disciplinary physics: materials science; rheology; Deposition; Emission; Exact sciences and technology; Gallium nitrides; Indium gallium nitrides; Materials science; Methods of crystal growth; physics of crystal growth; Methods of deposition of films and coatings; film growth and epitaxy; Nanoscale materials and structures: fabrication and characterization; Other topics in nanoscale materials and structures; Physics; Silicon substrates; Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2014.03.025

The technique of depositing a temperature-graded AlN buffer layer for crack-free GaN growth on Si substrate is demonstrated. Compared with the previously reported methods of buffer growth, this technique has the advantages of a thinner buffer layer for effectively producing compressive stress and simple binary growth without the need of changing its composition. By combining with an inter-layer structure of three-period GaN/AlN superlattice, crack-free growth of thick GaN layers of 3.7μm in total thickness is implemented. Also, the different emission behaviors of overgrown InGaN/GaN quantum wells (QWs) under different stress conditions with different graded temperature numbers are illustrated. It is found that the QW sample with the highest graded temperature number for depositing the AlN buffer has the weakest residual tensile stress, the shortest emission wavelength, the weakest carrier localization effect, the weakest quantum-confined Stark effect, and the highest internal quantum efficiency, even though the total indium content is about the same as those of other samples with significantly stronger residual stresses. •Use a temperature-graded AlN buffer for crack-free GaN growth on Si substrate.•Show the emission behavior of InGaN/GaN QW with temperature-graded buffer.•Weakest residual stress corresponds to the highest internal quantum efficiency.