Growth and Characterization of Epitaxial InN Films on Sapphire Substrate using an ArF Excimer Laser-Assisted Metalorganic Vapor-Phase Epitaxy (LA-MOVPE)

Kasashima

Sugita

et al. 2005

phys. stat. sol. (c)

An InN film is grown using an ArF excimer laser assisted-MOVPE where a high NH 3 decomposition rate condition is realized because of the effective dissociation of NH 3 by the ArF laser. Grown films show unusual phenomena such that amount of metallic In involved in a grown InN film is increased with increasing NH 3 flow rate during the growth. Through the annealing of grown InN films in the NH 3 flow, it is revealed that the photolysis of NH 3 by the ArF laser irradiation causes the decomposition of InN and, as a result of it, the formation of In droplets. The direction of the source gases injection during the growth, perpendicular or parallel to the substrate surface, has a significant effect on the formation of metallic In. Compared with the perpendicular injection, the parallel injection can suppress the formation of In droplets and allow us to grow InN at a higher temperature. A high density of atomic hydrogen (H) generated by the photolysis of NH 3 seems to take nitrogen atoms away from InN, leaving metallic In on the surface..

Section: Introductionmentioning

confidence: 99%

MOVPE growth of InN under high NH ₃ decomposition rate conditions

Kasashima

Sugita

et al. 2005

phys. stat. sol. (c)

“…The color of the film is changed from black for the 600 1C-grown film to yellow for the RTgrown one. The color change is due to the change in composition of the films; In 2 O 3 content is increased with decreasing deposition temperature [3]. The sources for oxygen seem to be H 2 O and/or O 2 incorporated into the chamber during the substrate loading.…”

Section: Resultsmentioning

confidence: 99%

“…Using the ArF laser-induced MOCVD system [2,3], InN x O y films are grown with trimethylindium (TMI) and NH 3 as sources. As substrates, 10 Â 10 mm 2 size (0 0 0 1) sapphire and 18 Â 18 mm 2 size glass sheet are used.…”

Section: Methodsmentioning

confidence: 99%

“…We have shown that the laser-induced MOCVD enables to grow InN-based films in a wide range of growth temperature, from RT to 700 1C. The films grown at a temperature less than 450 1C were found to contain a large amount of oxygen and to have a lattice constant larger than that of the pure InN [3]. Therefore, such a film is concluded to be an alloy of InN and In 2 O 3 , InN x O y .…”

Section: Introductionmentioning

confidence: 95%

“…For example, the decomposition rate is as low as 3.8% even at 700 1C [1]. In order to solve this problem, we have developed the laser-induced MOCVD technique of InN [2,3], where an ArF excimer laser (l ¼ 193 nm) is employed to dissociate NH 3 photolytically. NH 3 has an absorption coefficient as high as 100-1000 cm À1 atm À1 for ultraviolet light with a wavelength 180-200 nm [4], and can be easily decomposed into NH 2 and H by absorbing photons with such a high energy [5].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A new photocatalyzer InNxOy film grown by ArF excimer laser-induced MOCVD at low temperature (RT∼200°C)

Journal of Crystal Growth

Miyanishi

Kunishige

et al. 2007

Using the ArF excimer laser-induced MOCVD method, InN x O y thin films are grown on a glass substrate. The photolytical decomposition of NH 3 enables to grow them even at room temperature. It is found that the InN x O y thin films grown at a temperature less than 250 1C show an excellent photocatalytic decomposition of H 2 S under UV irradiation, while the activity of the films grown at a temperature higher than 300 1C is very small, less than 1 4 of that for the low-temperature films. The excellent photocatalytic activity for the low-temperature films is closely related to the amorphous phase of the films. r

Growth of N‐polarity InN by ArF‐laser assisted MOVPE

Physica Status Solidi (a)

Kasashima

Miyanishi

et al. 2006

In this paper, the employment of the ArF excimer‐laser assisted nitridation of sapphire substrate is studied in the ArF‐laser assisted MOVPE (la‐MOVPE) of InN. An ArF excimer laser with an energy 50 mJ/pulse and a repetition rate 20 Hz is introduced parallel to the substrate surface. The surface morphology of InN film grown on α‐Al2O3 (0001) is found to be markedly dependent on the nitridation conditions for the sapphire substrate. When no nitridation is made, the surface of grown InN film is very rough and many In droplets are found on it. A film with a mixture of rough‐surface region with In droplets and smooth‐surface region is grown on the thermally‐nitrided substrate (1000 °C for 30 min). By employing the ArF‐laser irradiation to the NH3 flow during the substrate nitridation at 1000 °C for 30 min (la‐nitridation), a smooth surface region is expanded to the entire surface of film. The smooth surface is found to be stable at growth temperature higher than 700 °C. The KOH etching of grown films reveals that the smooth surface has 5–10 time higher etching rate than the rough one. From these facts, it is concluded that the film with the smooth surface has N‐polarity. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)