Characterization of InN layers grown by high-pressure chemical vapor deposition

Abstract

Structural and optical properties of indium nitride ͑InN͒ layers grown by high-pressure chemical vapor deposition ͑HPCVD͒ on sapphire and GaN epilayers have been studied. HPCVD extends processing parameters beyond those accessible by molecular beam epitaxy and metal organic chemical vapor deposition, enabling the growth of epitaxial InN layers at temperatures as high as 1150 K for reactor pressures around 15 bars, leading to vastly improved material properties. InN layers grown on GaN͑0002͒ epilayers exhibit single-phase InN͑0002͒ x-ray diffraction peaks with full width at half maximum ͑FWHM͒ around 430 arc sec. Optical characterization of the InN layers by infrared ͑IR͒ reflectance reveals free carrier concentrations in the low to mid-10 +19-cm −3 and optical dielectric function ϱ = 5.8. The optical properties in the visible and near IR spectral ranges were analyzed by transmission spectroscopy, showing an absorption edge around 1.5 eV. The shift of the absorption edge correlates with deviations in the InN stoichiometry, indicating that the understanding and control of the point defect chemistry of InN is critical for improved material properties.

Growth temperature dependences of InN films grown by MOCVD

“…The growth temperature is limited by the desorption of nitrogen and thermal decomposition of the films [7]. Bulk material is not available but high quality films on sapphire have been fabricated by molecular beam epitaxy [5,8] and also MOCVD [9][10][11]. Singh et al characterized MOCVD grown InN films prepared with various growth conditions [12][13].…”

Optical properties of AlN thin films grown by plasma enhanced atomic layer deposition

“…The transfer matrix was used to calculate IR reflectance spectra from the multilayer structures (Air/AlN/sapphire). 17 The phonon contribution arises from lattice vibrations under the propagating electric field of the incident light modeled using a Lorentz oscillator. The frequency dependent complex dielectric function is…”

Self-limiting low-temperature growth of crystalline AlN thin films by plasma-enhanced atomic layer deposition

“…Use of temperaturesensitive device layers (e.g. In-rich In x Ga 1 − x N [20]) and substrates (e.g. flexible polymeric substrates), therefore, necessitates the adaptation of low-temperature growth methods.…”