Atomic layer doping for Si

We report on initial results of the potential of self-limiting surface reactions for the doping of Si layers using molecular beam epitaxy (MBE) and atmospheric pressure chemical vapor deposition (APCVD). In MBE experiments using Sb as an n-type dopant a self-limiting process is obtained at a coverage of half a monolayer. No evidence of a self-limiting process has yet been found for p-type doping using B2H6 above 400 °C. In the case of MBE growth at temperatures below 400 °C the B is only partly activated (10%-20%). In APCVD grown samples B surface coverage leads to significant growth inhibition of the subsequent deposition of Si from SiCl2H2. Finally, preliminary results of atomic layer doping using AsH3 in APCVD indicate a self-limitation of chemisorption of AsH3 at about 0.1 monolayer at a temperature of 600 °C; however, subsequent growth of Si leads to a smearing out of the As due to segregation and to the residence time of As in the system. © 1993.