EFFECT OF IONIZATION AND ACCELERATION OF AS-SOURCE BEAM ON LOW-TEMPERATURE EPITAXIAL-GROWTH OF GAAS ON EXACT (100)SI

The growth of GaAs films on on-axis (100) Si was studied using ionized source beam epitaxy (ISBE) at the growth temperatures in the range of 160-280-degrees-C. A single crystal GaAs layer could be epitaxially g rown on Si at a substrate temperature as low as 160-degrees-C by using an accelerated partially ionized As-source beam. Both ionization and acceleration of the As beam enhanced two-dimensional growth of GaAs ev en when As-incorporation was not a rate-limiting factor. It is believe d, however, that the energy required for the single crystal growth (es pecially at a temperature as low as 160-degrees-C) was mostly provided by the acceleration of the ionized source beam. The quality of the Ga As crystal depended on the As-to-Ga flux ratio. Both ionization and ac celeration of the As-beam gave rise to an increase in the GaAs growth rate in situations where As-incorporation could be one of the rate-lim iting steps in the growth of the GaAs crystal. The surface morphology, crystallinity, and microstructure of the epitaxial GaAs films grown o n Si (100) were evaluated using in situ reflection high energy electro n diffraction, X-ray diffraction, and cross section transmission elect ron microscopy.