Growth of GaN on sapphire (0001) using a supersonic jet of plasma-generated atomic nitrogen

Abstract

We describe a new GaN film growth method employing a supersonic jet of nitrogen atoms and a gallium effusion cell. The nitrogen atoms were generated by exciting a 1% nitrogen in helium mixture with a radio frequency discharge. X-ray diffraction and in situ reflection high-energy electron diffraction indicate that GaN films grown on sapphire ͑0001͒ were single crystalline and epitaxial with a rough surface morphology. A GaN growth rate of approximately 0.65 m/h was measured, independent of substrate temperature over the range of 600-750°C. However, the crystalline quality of the film increases markedly with increasing wafer temperature.

Corona discharge supersonic free-jet for III–V nitride growth via A 3Σu+ metastable nitrogen molecules

“…Various electrical discharges are employed to ''activate'' nitrogen, including radio frequency ͑rf͒ discharges, 4,5 microwave discharges, 6 electron cyclotron resonance ͑ECR͒ discharges, [7][8][9] arc-jet discharges, 10,11 and hollow anode plasma discharges. 12 These discharges often yield A 3 ⌺ u ϩ , but are invariably accompanied by numerous other electronically excited states of nitrogen atoms, molecules, and even ions.…”

Nitrogen species from radio frequency plasma sources used for molecular beam epitaxy growth of GaN

“…The principal types of source are the electron cyclotron resonance (ECR) microwave source and the radio frequency (RF) source. Other sources, including the supersonic jet [6], the cold cathode ion gun [7] and the Kaufman ion gun [8] are, arguably, of less importance. All these sources produce a nitrogen flux consisting of a mixture of neutral molecular, charged molecular, ionic and neutral atomic species together with free electrons.…”

Application of Supersonic Molecular Jets in Semiconductor Thin Film Growth

“…A growth rate of 0.6 µm/h that is only slightly lower than typical MOCVD growth rates of 1 µm/h was obtained with a nitrogen atom supersonic jet with an estimated flux on the order of 1 × 10 16 atoms cm -2 s -1 . 71,90 The FWHM of high-resolution X-ray diffraction peaks is comparable with GaN from other plasmaassisted MBE techniques, but it is relatively poor in comparison with the best MOCVD material. The highest GaN growth rates of 8 µm/h were reported with a supersonic arcjet of nitrogen atoms.…”