The addition of Sb as a surfactant to GaN growth by metal organic vapor phase epitaxy

Abstract

The role and effect of the isoelectronic center Sb on the structure and properties of GaN epilayers have been investigated. The gas phase Sb concentration was varied by changing the triethyl antimony/trimethyl gallium mole ratio over a wide range of concentrations while keeping other growth parameters constant. The Sb addition slightly improved the optical and structural properties of GaN epilayer at a low level of Sb incorporation, especially for the films grown under a high group V/III ratio conditions. The addition of Sb resulted in changes in GaN surface morphology, which was further explored by the lateral epitaxy overgrowth ͑LEO͒ technique through the changes in the growth rates and the facet formation. The presence of Sb in the gas phase greatly enhanced the lateral overgrowth rate and altered the formation of the dominant facets. Vertical facets to the LEO growth appeared with the addition of Sb under conditions that normally produced sloped sidewalls. While Sb altered the growth facet present during LEO, only a small amount of Sb was incorporated into the GaN, suggesting that Sb acts as a surfactant during the GaN metal organic vapor phase epitaxy growth. Sb addition produces surface conditions characteristic of a Ga-rich surface stoichiometry indicating both a possible change in the reactivity of NH 3 and/or enhanced surface diffusion of Ga adatom species in the presence of Sb.

Sb and Bi surfactant effects on homo-epitaxy of GaAs on () patterned substrates

“…Sb and Bi containing organometallics are already widely used in commercial and research reactors for doping (in group IV semiconductors) and alloying (in III/V semiconductors). The surfactant effects of Sb have been studied on GaInP [6][7][8][9][10][11][12], GaN [13][14][15], (GaIn)(NAsSb) [16], InGaAs [17], and GaAs [18,19]. Bi surfactant effects have been studied on GaInP [7,9], GaAs [19], InGaAs [20,17], InGaNAs [21], Si [22], and during the fabrication of InAs quantum dots [23].…”

Intermixing studies in GaN_1−xSb_x highly mismatched alloys

“…Prior to that work, the maximum concentrations reported by gas-source MBE were x∼0.26% [14,15] at a growth temperature of 750°C and x∼1% [16] at 500°C, respectively. These results suggest that the solubility limit of As in GaN is a function of temperature [17]. Zhao, et al, [16], has suggested that As acts mainly as a surfactant for temperatures over 700 C and that the GaN surface morphology improved in the presence of As at these high temperatures.…”

“…Both Sb and As have been used as surfactants to stabilize the growth front during SiGe growth [19][20]. Zhang, et al, used Sb as a surfactant in MOVPE growth of GaN at temperatures of 1000-1100 C and found a slight improvement in the optical and structural properties, particularly for films grown under high V/III ratio conditions [17]. One expects the solid solubility of Sb in GaN to be low due to the large difference in covalent radii and electronegativity, even larger than those for As in GaN [21][22].…”

Epitaxial growth of AlN on Cu(111) substrates using pulsed laser deposition

“…It is interesting to note that antimony works as a well-known surfactant in the epitaxial growth of various films, such as SiGe [23], GaNAs [24,25] and GaN [26], where it segregates to the growing surface and affects the surface properties, such as the surface energy, the reconstruction, and the surface kinetics. The fact that Sb segregation on the AlN surface was not observed in the case of PLD growth of AlN on Cu is explained, probably by the assumption that the AlN/Cu heterointerface provides more stable sites than the growing surface.…”