Laser-assisted metalorganic molecular beam epitaxy of GaAs

Abstract

We report preliminary studies of the growth of homoepitaxial GaAs by laser-assisted metalorganic molecular beam epitaxy, using triethylgallium (TEGa) and As4 sources and a 193 nm ArF excimer laser. Laser irradiation results in a high, selective-area growth rate at temperatures below 450 °C, where pyrolytic growth is very slow. The process is extremely efficient, with roughly unit probability for impinging TEGa molecules sticking and being dissociated by laser radiation to form GaAs. From the strong dependence on laser fluence, the growth enhancement process appears to be pyrolytic in nature (because of transient heating by the pulsed laser) and not photolytic. The cross section for photolysis must be at least ten times lower than the gas-phase value (9×10−18 cm2). The surface morphology of films grown at 400 °C is rough at threshold fluences (∼0.10 J/cm2), but becomes smooth at higher fluences (∼0.13 J/cm2). These regions with relatively smooth surfaces exhibit enhanced photoluminescence yields compared to areas receiving less intense laser radiation.

Photoassisted physical vapor epitaxial growth of semiconductors: a review of light-induced modifications to growth processes

“…82,83,86 Again, improved molecular dissociation rates can lead to an increase in the growth rate, as observed by several groups. 82,83,86,87 In many cases, improved surface morphology was also observed in cases where growth was intentionally carried out under kinetically limited conditions. 74,88 Given that several growth processes may be operative during OMVPE, and that those processes are highly dependent on the specific growth conditions (i.e.…”

“…Photogenerated carriers can therefore participate in the molecular dissociation process, perhaps through the elimination of an ethyl-metal bond by a hole [84,85,88]. Again, improved molecular dissociation rates can lead to an increase in the growth rate, as observed by several groups [84,85,88,89]. In many cases, improved surface morphology was also observed in cases where growth was intentionally carried out under kinetically limited conditions [76,79].…”

Molecular Beam Epitaxy with Gaseous Sources

“…Excimer lasers (wavelength: 193-248 nm) [91,92], Ar ion lasers (488 nm, 514.5 nm) [93,94], and N 2 lasers (337 nm) [95] may be used. Laser-assisted MOMBE is the growth method that changes the decomposition process and modifies the growth process by irradiating the laser light on the substrate surface during growth.…”

“…Doping Characteristics for n-type Gaseous Dopant Sources 1 Â 10 19 cm À3 >5 Â 10 19 cm À3Source: After Refs[90,91].…”

Tailoring Heterovalent Interface Formation with Light

“…Light stimulation of the growth surface offers an additional parameter with which to alter growth processes [7][8][9][10][11][12][13][14][15]28]. In particular, it has been shown to improve the crystal quality of II-VI semiconductor epilayers grown at temperatures as low as 150°C and has helped to improve extrinsic doping efficiency [16,17].…”