Silicon n-p-n junction transistors have been made from rate-grown single crystals. Using gallium and antimony as doping agents, single crystals of n-type silicon have been grown containing up to five p-regions from 0.0005 to 0.002 inches wide which are suitable for the production of transistors. The ohmic contact to the p-type base region was made by alloying an aluminum wire using techniques similar to those employed in the fabrication of aluminum-silicon diodes. The electrical evaluation of n-p-n transistors produced from these single crystals is described. Alphas in excess of 0.9 at -1 ma emitter current have been obtained, and collector saturation currents of 10-6ampere/cm2 are common. With base-layer widths of about 0.0005 inch, the alpha cutoff occurs at approximately 5 megacycles. The units (approximately 0.04×0.04×0.5 inches in size) have been operated at power levels in excess of 1.5 watts in air with no special provision for heat dissipation.