Relaxation and critical strain for maximum In incorporation in AlInGaN on GaN grown by metal organic vapour phase epitaxy

Abstract

Articles you may be interested in X-ray characterization of composition and relaxation of Al x Ga 1 − x N ( 0 ≤ x ≤ 1 ) layers grown on GaN/sapphire templates by low pressure organometallic vapor phase epitaxy J. Appl. Phys. 108, 043526 (2010); 10.1063/1.3457149Oxygen induced strain field homogenization in AlN nucleation layers and its impact on GaN grown by metal organic vapor phase epitaxy on sapphire: An x-ray diffraction study Quaternary AlInGaN layers were grown on conventional GaN buffer layers on sapphire by metal organic vapour phase epitaxy at different surface temperatures and different reactor pressures with constant precursor flow conditions. A wide range in compositions within 30-62% Al, 5-29% In, and 23-53% Ga was covered, which leads to different strain states from high tensile to high compressive. From high-resolution x-ray diffraction and Rutherford backscattering spectrometry, we determined the compositions, strain states, and crystal quality of the AlInGaN layers. Atomic force microscopy measurements were performed to characterize the surface morphology. A critical strain value for maximum In incorporation near the AlInGaN/GaN interface is presented. For compressively strained layers, In incorporation is limited at the interface as residual strain cannot exceed an empirical critical value of about 1.1%. Relaxation occurs at about 15 nm thickness accompanied by strong In pulling. Tensile strained layers can be grown pseudomorphically up to 70 nm at a strain state of 0.96%. A model for relaxation in compressively strained AlInGaN with virtual discrete sub-layers, which illustrates the gradually changing lattice constant during stress reduction is presented. V C 2012 American Institute of Physics. [http://dx.

Polarization-Engineered Enhancement-Mode High-Electron-Mobility Transistors Using Quaternary AlInGaN Barrier Layers

“…The In incorporation at the lowest surface temperature of 719°C is thickness dependent because of In pulling effects, which are observed for compressively strained layers. 11 This is also obvious in the RBS spectrum in Fig. 1 for the 75 nm reference layer, which shows an increasing In signal from the interface to the surface.…”

“…Here, the bowing parameters are updated by the latest results from the literature: The bowing parameters used here are 0.9 eV for AlGaN, 17 1.65 eV for InGaN, 17 and a quite high and constant value of 5.2 eV for AlInN. 11,18 The bowing parameter for AlInN is still vague and might also be In dependent, especially for the In-rich region. 17 The contour lines in the quaternary area illustrate the total polarization of quaternary barriers for the corresponding barrier composition, being pseudomorphically grown on a GaN buffer.…”

“…Further, barrier layers under high compressive strain show effects such as relaxation and In pulling, which degrade device characteristics even further and impede process control and reproducibility. 10,11 Here, we present a different approach of a simultaneously lattice-matched and polarization-reduced AlInGaN/GaN heterostructure with improved crystal quality showing performance competitive to other concepts for nitride-based e-mode transistors. A comparison with a compressively strained heterostructure is also given.…”

Alteration of structural and optical properties in quaternary Al0.1In0.1Ga0.8N films using ultraviolet assisted photo-electrochemical etching route

“…Keeping pace with research and investigation carried out thus far on the III-nitrides semiconductors, stemming from binary GaN to ternary Al x Ga 1-x N and In y Ga 1-y N [11][12][13][14][15][16][17], as well as quaternary Al x In y Ga 1-x-y N [18][19][20], significance of growing optimum III-nitrides heterostructures for quantum wells with regards to the LEDs performance is unveiled.…”

“…A C C E P T E D ACCEPTED MANUSCRIPT 4 Various approaches have been attempted to optimize the Al x In y Ga 1-x-y N layers grown on GaN, either by manipulating growth conditions [18,28] or by varying Al/In contents [18-19, 21, 29] in the quaternary layers. Though a lattice matched Al x In y Ga 1-x-y N layer with reduced strain-related defects and built-in polarization field could be attained after optimization, analogous effect might not be achieved for Al x In y Ga 1-x-y N layers produced either under different growth conditions or with dissimilar In contents.…”