In atomic layer doping of P using an ultraclean low-pressure chemical vapor deposition (CVD), the relationship between surface segregation of P during Si cap layer growth at 450 °C with Si2H6 partial pressure of 3-20 Pa on P atomic layer formed on Si0.3Ge0.7/Si(100) and the incorporated P amount at initial position has been investigated. For higher Si2H6 partial pressure and for the initial P atom amount of P atomic layer below about 4 × 1014 cm- 2, the incorporated P atoms are almost confined within the 1 nm region around the heterostructure interface. The P amount is nearly the same as the initial one. For initial P atom amount higher than 4 × 1014 cm- 2, P segregation on surface is enhanced, and the incorporated P atom amount around the heterointerface tends to saturate to maximum value of about 4 × 1014 cm- 2. This maximum value decreases with decreasing Si2H6 partial pressure. These results suggest that the number of site at the heterointerface between Si cap layer and Si0.3Ge0.7 layer, in which P atoms are incorporated, is about 4 × 1014 cm- 2 and in the case of low Si2H6 surface coverage, the incorporated P atom amount at the heterointerface decreases due to surface segregation.
- Atomic-layer doping
- Chemical vapor deposition (CVD)
- Si epitaxial growth