scholarly journals Determination of Temperature-Dependent Stress State in Thin AlGaN Layer of AlGaN/GaN HEMT Heterostructures by Near-Resonant Raman Scattering

2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Yanli Liu ◽  
Xifeng Yang ◽  
Dunjun Chen ◽  
Hai Lu ◽  
Rong Zhang ◽  
...  
Keyword(s):  
Stress State ◽  
Raman Scattering ◽  
Barrier Layer ◽  
Algan Layer ◽  
Temperature Dependent ◽  
Gan Hemt ◽  
Algan Barrier ◽  
Algan Barrier Layer ◽  
Resonant Raman ◽  
Resonant Raman Scattering

The temperature-dependent stress state in the AlGaN barrier layer of AlGaN/GaN heterostructure grown on sapphire substrate was investigated by ultraviolet (UV) near-resonant Raman scattering. Strong scattering peak resulting from the A1(LO) phonon mode of AlGaN is observed under near-resonance condition, which allows for the accurate measurement of Raman shifts with temperature. The temperature-dependent stress in the AlGaN layer determined by the resonance Raman spectra is consistent with the theoretical calculation result, taking lattice mismatch and thermal mismatch into account together. This good agreement indicates that the UV near-resonant Raman scattering can be a direct and effective method to characterize the stress state in thin AlGaN barrier layer of AlGaN/GaN HEMT heterostructures.

Impact of strain relaxation of AlGaN barrier layer on the performance of high Al-content AlGaN/GaN HEMT

2006 ◽  
Vol 49 (4) ◽  
pp. 393-399 ◽  
Author(s):  
Yan Yang ◽  
Yue Hao ◽  
Jincheng Zhang ◽  
Chong Wang ◽  
Qian Feng
Keyword(s):  
Barrier Layer ◽  
Strain Relaxation ◽  
Al Content ◽  
Gan Hemt ◽  
Algan Barrier ◽  
Algan Barrier Layer ◽  
High Al Content

Growth and Characterization of AlGaN/AlN/GaN HEMT Structures with a Compositionally Step-Graded AlGaN Barrier Layer

2007 ◽  
Vol 24 (6) ◽  
pp. 1705-1708 ◽  
Author(s):  
Ma Zhi-Yong ◽  
Wang Xiao-Liang ◽  
Hu Guo-Xin ◽  
Ran Jun-Xue ◽  
Xiao Hong-Ling ◽  
...  
Keyword(s):  
Barrier Layer ◽  
Gan Hemt ◽  
Algan Barrier ◽  
Algan Barrier Layer

Effects of NH3 Flow Rate During AlGaN Barrier Layer Growth on the Material Properties of AlGaN/GaN HEMT Heterostructure

2017 ◽  
Vol 46 (10) ◽  
pp. 6104-6110 ◽  
Author(s):  
Franky J. Lumbantoruan ◽  
Yuen-Yee Wong ◽  
Wei-Ching Huang ◽  
Hung-Wei Yu ◽  
Edward-Yi Chang
Keyword(s):  
Flow Rate ◽  
Barrier Layer ◽  
Material Properties ◽  
Layer Growth ◽  
Gan Hemt ◽  
Algan Barrier ◽  
Algan Barrier Layer

scholarly journals Temperature-dependent resonant Raman scattering study of core/shell nanocrystals

2007 ◽  
Vol 92 ◽  
pp. 012045 ◽  
Author(s):  
V M Dzhagan ◽  
M Ya Valakh ◽  
A E Raevskaya ◽  
A L Stroyuk ◽  
S Ya Kuchmiy ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Core Shell ◽  
Temperature Dependent ◽  
Scattering Study ◽  
Resonant Raman ◽  
Resonant Raman Scattering

Back-Doping Design in AlGaN/GaN Heterostructure Field-Effect Transistors for High-Power Applications

2001 ◽  
Vol 693 ◽  
Author(s):  
Narihiko Maeda ◽  
Kotaro Tsubaki ◽  
Tadashi Saitoh ◽  
Naoki Kobayashi
Keyword(s):  
Barrier Layer ◽  
High Power ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Algan Layer ◽  
Barrier Layers ◽  
Algan Barrier ◽  
Heterostructure Field Effect Transistors ◽  
Algan Barrier Layer ◽  
Gan Heterostructure

AbstractA novel doping design has been proposed that yields high two-dimensional electron gas (2DEG) densities in the AlGaN/GaN heterostructure field-effect transistors (HFETs) even when the AlGaN barrier layers are designed to be very thin. In the novel doping design, an asymmetric double-heterostructure is employed, and donor atoms are doped not only in the surface-side AlGaN layer but also in the underlying AlGaN layer. In this structure, electrons are efficiently supplied also from the back-doped AlGaN barrier layer to the GaN channel, with the help of the negative polarization charges at the heterointerface between the GaN channel and the underlying AlGaN barrier layer. High 2DEG densities can thus be obtained. Moreover, relatively high 2DEG mobilities can be obtained for high 2DEG densities, because back-doped donor atoms are sufficiently remote from the position of the 2DEG so that the 2DEG is less subjected to the ionized impurity scattering due to the relevant donor atoms. By using this back-doping design, a very high 2DEG density of 2.8x1013 cm-2 (2DEG mobility is 850 cm2/Vs) has been obtained at 300 K in the Al0.3Ga0.7N/GaN HFET whose barrier layer (Al0.3Ga0.7N) is as thin as 120 Å. Thus, the back-doping design is effective to obtain high 2DEG densities in the HFETs with thin barrier layers, and promising for high-power applications.

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