I. Berishev et al., HIGH GROWTH-RATE GAN FILMS USING A MODIFIED ELECTRON-CYCLOTRON-RESONANCE PLASMA SOURCE, Journal of vacuum science & technology. A. Vacuum, surfaces, and films, 16(5), 1998, pp. 2791-2793
Citations number
11
Categorie Soggetti
Physics, Applied","Materials Science, Coatings & Films
GaN thin films were deposited by reactive molecular beam epitaxy metho
d with a modified ASTeX(R) compact electron cyclotron resonance (ECR)
plasma source of nitrogen. The effect of different ECR exit apertures
on the growth rate and photoluminescence properties of GaN films was i
nvestigated. An aperture with a matrix of 1.6 mm holes allowed for GaN
films with good optical properties at growth rates up to 1 mu m/h. Ap
ertures of larger diameter resulted in semi-insulating films. Room tem
perature photoluminescence for both undoped and Si-doped GaN films wit
h full width at half maximum less than 100 meV has been obtained at th
e highest growth rates. We suggest that such an aperture effectively b
locks the energetic ions from reaching the substrate thus reducing ion
damage, resputtering, and increasing the Ga surface population. It al
so creates a higher pressure inside the ECR resonator, and therefore,
provides a higher flux of active species. While further optimization w
ill result in better GaN film quality, our results suggest that the gr
owth rate in Ga-rich condition is limited by the microwave power avail
able in the ASTeX compact ECR source. (C) 1998 American Vacuum Society
. [S0734-2101 (98)06105-3].