The thermal oxidation of Ge-implanted Si single crystals has been investigated for different Ge doses (3x10(15) cm(-2) and 3x10(16) cm(-2)) and different oxidation processes (in wet ambient at 920 degreesC for 30, 60, and 120 min, or dry ambient at 1100 degreesC for 30 min). The oxide roughness, the oxidation rate, the Ge diffusion, precipitation, and clustering, have been monitored by several experimental techniques: atomic force microscopy, transmission electron microscopy, Rutherford backscattering spectrometry, and x-ray absorption spectroscopy. We found that the surface roughness is related to the segregation of Ge at the oxide/substrate interface, occurring when the oxidation rate is faster than the Ge diffusion, in particular at the higher implanted dose (3x10(16) cm(-2)) when processed in a wet ambient. For these conditions, we also observed an oxidation rate enhancement with respect to pure Si, and a strong indication that pure Ge clusters were formed. When a critical Ge concentration at the interface is reached, the oxidation mechanisms change and the oxidation rate is reduced, along with Ge diffusion into the substrate and a consequent reduction of the Ge fraction at the interface. Nevertheless, the oxide roughness still increases despite the Ge concentration reduction, resulting from the initial nucleation of precipitates. (C) 2002 American Institute of Physics. RI Raineri, Vito/C-5307-2009; La Via, Francesco/E-8035-2011
Thermal oxidation of Si (001) single crystal implanted with Ge ions
TERRASI, Antonio;
2002-01-01
Abstract
The thermal oxidation of Ge-implanted Si single crystals has been investigated for different Ge doses (3x10(15) cm(-2) and 3x10(16) cm(-2)) and different oxidation processes (in wet ambient at 920 degreesC for 30, 60, and 120 min, or dry ambient at 1100 degreesC for 30 min). The oxide roughness, the oxidation rate, the Ge diffusion, precipitation, and clustering, have been monitored by several experimental techniques: atomic force microscopy, transmission electron microscopy, Rutherford backscattering spectrometry, and x-ray absorption spectroscopy. We found that the surface roughness is related to the segregation of Ge at the oxide/substrate interface, occurring when the oxidation rate is faster than the Ge diffusion, in particular at the higher implanted dose (3x10(16) cm(-2)) when processed in a wet ambient. For these conditions, we also observed an oxidation rate enhancement with respect to pure Si, and a strong indication that pure Ge clusters were formed. When a critical Ge concentration at the interface is reached, the oxidation mechanisms change and the oxidation rate is reduced, along with Ge diffusion into the substrate and a consequent reduction of the Ge fraction at the interface. Nevertheless, the oxide roughness still increases despite the Ge concentration reduction, resulting from the initial nucleation of precipitates. (C) 2002 American Institute of Physics. RI Raineri, Vito/C-5307-2009; La Via, Francesco/E-8035-2011I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.