Growth model for plasma-assisted molecular beam epitaxy of N-polar and Ga-polar InxGa1−xN

Abstract

The authors have developed a comprehensive model for the growth of N-polar and Ga-polar In x Ga 1−x N by N 2 plasma-assisted molecular beam epitaxy. GaN films of both polarities were coloaded and In x Ga 1−x N was grown in the composition range of 0.14Ͻ x Ͻ 0.59 at different growth temperatures keeping all other conditions identical. The compositions were estimated by triple-axis-2 x-ray diffraction scans as well as by room temperature photoluminescence measurements. The dependence of the In composition x in In x Ga 1−x N on growth temperature and the flux of incoming atomic species is explained using a comprehensive growth model which incorporates desorption of atomic fluxes as well as decomposition of InN component of In x Ga 1−x N. The model was found to be in good agreement with the experimental data for In x Ga 1−x N of both polarities. A N-polar In 0.31 Ga 0.69 N / In 0.05 Ga 0.95 N multi-quantum-well structure grown with conditions predicted by our growth model was found to match the compositions of the active layers well besides achieving a smooth surface morphology at the quantum-well/barrier interface. The understanding of growth kinetics presented here will guide the growth of In x Ga 1−x N for various device applications in a wide range of growth conditions.

Unipolar vertical transport in GaN/AlGaN/GaN heterostructures

“…As shown in the energy band diagram ( Figure 3(c)), a thin InGaN 20 layer provides a polarization-induced dipole that creates an electrostatic barrier that would not be permeable to percolation effects. The InGaN layer was grown in In-rich conditions using a Ga/N flux ratio of 0.40 at a temperature of 540 C. [20][21][22][23] In the energy band diagram simulation, background density of 10 16 cm À3 n-type dopants for GaN layer was included. The AlGaN layer was used to further provide a dipole at the UID GaN/AlGaN interface, which leads to a flat energy band profile at equilibrium.…”

InGaN/GaN tunnel junctions for hole injection in GaN light emitting diodes

“…InGaN was grown in In-rich conditions using a growth model reported elsewhere with a Ga flux less than stoichiometry. 26 By pulsing the nitrogen shutter with a duty cycle of 50%, high doping in n + -GaN (1.2 x 10 20 cm -3 ) was achieved. The structure was terminated with an n-type GaN (260 nm, 2.5 x 10 19…”

Demonstration of forward inter-band tunneling in GaN by polarization engineering

“…The N-polar orientation of GaN was used in this work to achieve high composition InGaN for efficient inter-band tunneling. N-polar InGaN was grown using the conditions and growth model developed earlier 14,15 . InGaN was grown at a substrate temperature of 550 0 C followed by 70nm of p GaN (N A ~ 5 X 10 19 cm -3 ).…”