Siliconn‐p‐njunction transistors have been made from rate‐grown single crystals. Using gallium and antimony as doping agents, single crystals ofn‐type silicon have been grown containing up to fivep‐regions from 0.0005 to 0.002 inches wide which are suitable for the production of transistors. The ohmic contact to thep‐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 ofn‐p‐ntransistors 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/cm2are 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.