Buffer free direct growth of GaN on 6H–SiC by metalorganic vapor phase epitaxy

Abstract

The growth of GaN on 6H–SiC is three dimensional (3D) and results in the formation of large islands presenting hexagonal truncated shape with {1–101} lateral facets and a top {0001} facet. In this work, we present a three steps growth process that enables us to grow high quality mirrorlike GaN layers without using AlN buffer layers. During a first step, a thin 3D GaN layer is deposited at high temperature. This layer is smoothed under ammonia flow for several minutes when the growth is interrupted. The subsequent growth of GaN is two dimensional. 600 nm thick GaN films were grown. They were analyzed by high resolution x-ray diffraction, reflectivity, and photoluminescence. All the layers are under strong tensile biaxial strain. The correlation between residual tensile strain in GaN layers and their optical properties is reported for biaxial deformations εxx ranging up to 0.37%.

Influence of AlGaN nucleation layers on structural and electrical properties of GaN on 4H-SiC

“…If we calculate the relationship between measured a and c lattice parameters of our GaN layers assuming elastic deformation of the GaN unit cell, we obtain a value for the elastic stiffness coefficients À2C 13 =C 33 ¼ À0:451; which is in good agreement with published values ranging from -0.44670.03 [10] to -0.53 [11].…”

Strong coupling in bulk GaN microcavities grown on silicon

“…The value of the excitonic oscillator strengths used in the simulation is (35 000 ± 5000) meV 2 for A and B exciton. The C exciton is not considered due to its weak oscillator strength (less than 2000 meV 2 ) in the GaN layer under highly compressive strain [9,10]. The value of the energy separation between A and B exciton (15±2 meV) corresponds to the influence of this large biaxial strain on the valence band states.…”

AlGaN/GaN high electron mobility transistor grown by molecular beam epitaxy on Si(110): comparisons with Si(111) and Si(001)

“…The PL band edge of GaN is dominated by the neutral donor bounded exciton recombination. The energy position of the peak E PL = 3.469 eV indicates a low in plane biaxial tensile strain [15] ε xx of about 5×10 -4 . The energy position of the peak for GaN layers grown on Si(111) substrate (E PL = 3.468 -3.473 eV) indicates they are with a biaxial strain ε xx ranging from almost 0 to 6×10 -4 .…”