Deep levels in GaAs due to Si δ doping

Abstract

␦͑Si͒-doped GaAs samples grown by metalorganic vapor phase epitaxy are studied by capacitancevoltage and deep level transient spectroscopy ͑DLTS͒ techniques. A detailed analysis of the DLTS signal ͑including spatial profiles͒ is performed. DLTS spectra exhibit a clear development depending on the sheet dopant concentration ranging from 5ϫ10 14 to 2ϫ10 16 m Ϫ2 . Two observed peaks do not change its activation energy with the doping level while their amplitude increases rapidly when the doping rises. We assign them to defects generated by high silicon concentration, probably related to gallium vacancy. Another peak in the most densely doped sample seems to correspond to the DX level which is occupied near the ␦ layer. Peculiar features of the EL2 level are observed in ␦-doped GaAs and explained by the band bending due to the dopant sheet. No indication of the emission from the quantum confinement states is found in DLTS spectra taken at temperatures 80-400 K.

Identification of dislocation-related and point-defects in III-As layers for silicon photonics applications

“…indicate that with increasing t p , the peaks do not shift significantly toward lower temperatures. Based on this and on previous papers [25][26][27][28][29][30][31][32][33][34][35][36], we suggest that E1 and E3 originate from point defect located near dislocations, rather than from a dislocation core.…”

“…The investigation of the signature of E2 led us to hypothesize that it is associated with the oxygen related center EL3 (oc-O As ) [26][27][28][29][30][31]. The signature of trap E3 was found to be similar to a well-known GaAs native defect called EL2, that corresponds to an As antisite defect As Ga [25,29,[31][32][33][34][35]. Furthermore, trap E3 corresponds to a trap which was found to be related to threading dislocations in [37].…”