Gas Source Si-Mbe

Abstract

ABSTRACTGas source Si molecular beam epitaxy (Si-MBE) apparatus has been devised. The growth mechanism was studied using reflection high energy electron diffraction (RHEED) intensity oscillation. Si epitaxial layers grew through a dissociative adsorption of Si2H6 molecules on Si surfaces. This dissociative adsorption enables a selective epitaxial growth on SiO2 patterned Si wafers. At low temperatures, the growth rate was limited by a desorption of hydrogen which terminates surface dangling bonds. Doping with B, Sb and P were also studied. B doping was achieved using HBO2 Knudsen cell or B2H6 gas dopant. Sb doping used an ionized doping cell. P doping was achieved using PH3 gas dopant. The effect of B doping on the growth was studied using RHEED oscillation. A doped layer's selective epiataxial growth was possible by selective epitaxial growth under doping. This technique was applied to bipolar transistor fabrication. Moreover, using GeH4, Si1−xGex compound growth and its selective epitaxial growth was achieved. Using this Si1−xGex selectively grown layer, a Si1−xGex base heterobipolar transistor (HBT) was also fabricated. An electron cyclotron resonance (ECR) gas source Si-MBE cell was used for a low temperature surface cleaning and a surface termination by atomic hydrogen.