Crystallinity and morphology of InSb epitaxial layers grown on GaSb by MOVPE using TDMASb and TMSb as Sb precursors

High resolution X-ray diffraction (HRXRD), scanning probe microscopy (SPM), scanning electron microscopy (SEM), and optical microscopy measurements have been used for the crystallinity and morphological evaluation of epitaxial layers of InSb which were deposited on GaSb substrate using various V/III ratios and growth temperatures. Trimethylindium (TMIn) was used as indium source, while trisdimethylaminoantimony (TDMASb) and trimethylantimony (TMSb) were used comparably as antimony (Sb) source. Analysis of the micrographs obtained from the samples indicates that the thickness and quality of the deposited InSb layers are highly susceptible to changes in growth temperatures and V/III ratio regardless of the Sb source used. Fairly flat surfaces and optimum rms roughness values of 0.63 nm and 0.84 nm over 5 mu m(2) (relative to the rms roughness of 0.42 nm for the GaSb substrate) was achieved for the growth of InSb layers using values of VIII ratio which is approximate to 1.0 with growth temperatures of 480 degrees C and 425 degrees C for TMSb/TMIn and TDMASb/TMIn precursors respectively. The higher values of full width at half maximum (FWHM) from XRD patterns obtained for InSb layers deposited using TDMASb compared to TMSb indicates an improvement in crystallinity for the InSb layers deposited using TMSb as Sb source.

Automated summary

High resolution X-ray diffraction, scanning probe microscopy, scanning electron microscopy, and optical microscopy were used to evaluate the crystallinity and morphology of epitaxial layers of InSb deposited on GaSb substrate. The study showed that the thickness and quality of the deposited InSb layers are highly sensitive to changes in growth temperatures and V/III ratios, regardless of the Sb source used. Additionally, XRD patterns indicated an improvement in crystallinity for InSb layers deposited using TMSb compared to TDMASb.