Monolithic Hot Electron Transistors have been made in silicon using dopant implantation at low energies. A reverse biassed metal-semiconductor barrier was used as an emitter and a camel diode as a collector. A maximum available gain of >20 dbs was measured at low frequencies but the performance of these transistors was degraded by a large base contact series resistance. The FT increased with emitter current up to a value of 3 GHz and was determined solely by the charging time of the tunnel emitter.