X-ray and DLTS characterizations of In _x Ga_1−x As(x<0.03)/GaAs layers grown by VPE using an In/Ga alloy source

Abstract

In_xGa₁₋ xAs(x}<0.03)/GaAs lasers grown by vapor phase epitaxy using an In/Ga alloy source were characterized by double crystal X-ray (DCX) diffraction and deep level transient spectroscopy (DLTS) measurements. Based on the results obtained from (400), (511), and (¯511) DCX rocking curves, the obvious effect of In incorporation is to give an increase in the full width at half maximum of the rocking curves that correlates with a coherency of the epitaxial layers. From DLTS spectra according to the In content, the most prominent electron deep traps areE 4 (E _c-0.58eV) andE5 (E _c-0.84eV). TheE 4 trap density increases with In content while the change ofE 5 trap density is not monotonic. The trend ofE 5 trap densities versus In content is very similar to that of etch pit densities (EPDs), that is, a minimum in EPD andE 5 trap density is observed at an In content ofx∼0.003 but beyond this value the densities increase again with In content.