| AVS 64th International Symposium & Exhibition | |
| Spectroscopic Ellipsometry Focus Topic | Monday Sessions |
| Session EL+AS+EM+TF-MoM |
| Session: | Application of SE for the Characterization of Thin Films and Nanostructures |
| Presenter: | Chuanwei Zhang, Huazhong University of Science and Technology, China |
| Authors: | Y. Liang, Guangxi University, China H.G. Gu, Huazhong University of Science and Technology, China J. Xue, Xidian University, China C.W. Zhang, Huazhong University of Science and Technology, China Q. Li, Guangxi University, China Y. Hao, Xidian University, China S.Y. Liu, Huazhong University of Science and Technology, China Q. Yang, Guangxi University, China L. Wan, Guangxi University, China Z.C. Feng, Guangxi University, China |
| Correspondent: | Click to Email |
Indium aluminum nitride (InAlN), a prospective material for lattice matched confinement layer, possesses the potential to improve the reliability and performance of high electron mobility transistors (HEMTs).[1] One of the important advantages of InAlN alloy is the possibility of growing in-plane lattice-matched to GaN for an indium content of around 17%. However, the bandgap we expected is hindered by the growth of high-quality InAlN films due to the phase separation and nonuniform composition distribution.[1-2]
In this work, InAlN/GaN heterostructures, grown by pulsed metal organic chemical vapor deposition (PMOCVD) on c-plane sapphire substrates, were investigated by a dual rotating-compensator Mueller matrix ellipsometer (ME-L ellipsometer, Wuhan Eoptics Technology Co. Ltd., China). The experimental data (Ψ and ∆), covering the wavelength (λ) range from 193 nm up to 1700 nm at 1 nm step or energy (E) from 0.73 eV to 6.43 eV, were obtained by variable temperatures spectroscopic ellipsometric (VTSE) in three angles (50°, 55° and 60°). The Eoptics software was utilized to fit VTSE data using Tauc-Lorentz multiple oscillator modes. By analyzing the fitting results, the optical constants of the InAlN at variable temperatures (25℃-600℃) were obtained. The peak value of the refractive index increases from 269 nm to 284 nm with increasing temperature. The bandgaps are 4.57 eV and 4.35 eV at the temperature 25℃and 600℃, respectively. These results demonstrated that InAlN/GaN has a high thermal stability, scilicet no significant performance degradation in high temperature environment.
Reference
[1] Wenyuan Jiao, Wei Kong, Jincheng Li et al, Characterization of MBE-grown InAlN/GaN heterostructures valence band offsets with varying In composition, AIP ADVANCES 6, 035211 (2016).
[2] JunShuai Xue, JinCheng Zhang, Yue Hao, Investigation of TMIn pulse duration effect on the properties of InAlN/GaN heterostructures grown on sapphire by pulsed metal organic chemical vapor deposition, Journal of Crystal Growth 401, 661 (2014).