Low temperature selective silicon epitaxy by ultra high vacuum rapid thermal chemical vapor deposition using Si2H6, H2 and Cl2

Abstract

We present the use of the Si2H6/H2/CL2 chemistry for selective silicon epitaxy by rapid thermal chemical vapor deposition (RTCVD). The experiments were carried out in an ultrahigh vacuum rapid thermal chemical vapor deposition reactor. Epitaxial layers were grown selectively with growth rates above 150 nm/min at 800 °C and 24 mTorr using 10% Si2H6 and H2 and Cl2 with a minimum Si:Cl ratio of 1. Excellent selectivity with respect to SiO2 and Si3N4 was obtained indicating that very low Cl2 partial pressures are sufficient to preserve selectivity. In situ doping results with B2H6 show that sharp doping transitions and a wide range of B concentrations can be obtained with a slight B incorporation rate reduction with Cl2 addition. Our results indicate that UHV-RTCVD with the Si2H6/H2/Cl2 chemistry yields highly selective Si epitaxy with growth rates well within the practical throughput limits of single wafer manufacturing and with a potential to reduce the Cl content below the levels used in conventional SiH2Cl2 based selective epitaxy processes.

Rapid Thermal Processes for Future Nanometer MOS Devices

“…This structure must be fabricated with a relatively low thermal budget in order not to diffuse too deeply into the substrate during epitaxial growth and must be selective with respect to growth on oxide (or nitride). All of the required condition have been demonstrated in a cold wall RTP system [11].…”

“…RTP based selective epitaxy has been one of the most promising approaches to fabricating the elevated source/drain structure [11]. This structure must be fabricated with a relatively low thermal budget in order not to diffuse too deeply into the substrate during epitaxial growth and must be selective with respect to growth on oxide (or nitride).…”

Investigation of In-situ Boron-Doped Si Selective Epitaxial Growth by Comparison with Arsenic Doping

“…This indicates that B atoms are preferentially etched compared with Si atoms, similarly with As atoms. 25) To investigate the surface segregation of B atoms, we grew an undoped Si layer on an in-situ doped layer. We measured the depth profiles of the dopant concentrations in the undoped layers caused by surface segregation during the growth.…”

Isotropic/anisotropic growth behavior and faceting morphology of Si epitaxial layer selectively grown by cold wall ultrahigh vacuum chemical vapor deposition

“…The system has some advantages in terms of easy scale-up and enhanced selectivity over isolation materials due to the suppression of gas phase prereaction. [30][31][32] The growth temperature and the source gas flow rate were systematically varied to understand the role of process variables in the SEG morphological evolution. The change in SEG morphology with layer thickness was analyzed at various growth conditions.…”