Cathodoluminescence mapping, deep‐level transient spectroscopy, and electron‐beam‐induced current measurements on GaAs layers grown on Si substrates by metalorganic chemical vapor deposition

GaAs layers grown by organometallic chemical vapor deposition (OMCVD) on Si substrates oriented 2° off (100) toward [011] have been studied by 10‐K filtered cathodoluminescence, deep‐level transient spectroscopy (DLTS), electron‐beam‐induced current (EBIC), and secondary ion mass spectrometry (SIMS) measurements. The mapping of the near‐band‐edge emission intensity shows the existence of zones of lower defect density, whose relative volume increases with the layer thickness. Four deep‐level energy peaks have been characterized at 1.33, 1.20, 1.15, and 1.02 eV. The 1.33 and 1.20 eV energy peaks are attributed to Si in GaAs. Strong inhomogeneities in the intensity of these two emissions have been observed with depth of the layers, and this behavior has been related to the silicon distribution. From measurements on structures grown with different buffer layers, we show that a GaAs/AlAs supperlattice located at 1 μm from the Si substrate is efficient in decreasing the width of a highly Si‐doped interface regi...