Deep Levels in InP Grown by MOCVD

Abstract

Deep levels in the undoped InP grown by MOCVD have been investigated by deep level transient spectroscopy (DLTS). Three electron traps MOE1, MOE2, MOE3 have been observed with activation energies of 0.37 eV, 0.53 eV and 0.60 eV, respectively, in the temperature range between 160 K and 380 K. The trap concentrations of these levels were from 1013 cm-13 to 1015 cm-3 for samples with carrier concentrations of (1-6)×10-16 cm-3. The electron capture cross sections (σn) have been directly determined to be 3.1×10-18 cm2 (at 206 K) for MOE1 and 8.8×10-19 cm2 (at 344 K) for MOE3. For the level MOE2, it has been found that the capture cross section is strongly dependent on temperature, i.e., temperature dependence of this cross section is experimentally well-characterized by the relation σn=4.2×10-12 (cm2) exp (-0.38 (eV)/kT), which indicates the multiphonon emission process occurring during an electron capture event. Two deep levels have also been found in the LEC InP substrate material, which are identical to the defects observed in the epitaxial layer.