A planar doped 2D-hole gas base AlGaAs/GaAs heterojunction bipolar transistor grown by MBE.
01 January 1988
A new type of AlGaAs/GaAs heterojunction bipolar transistor which employs a 2D-hole gas base formed by planar doping using molecular beam epitaxy has been demonstrated. The base consists of a plane of Be atoms of sheet concentration 2.5x10 sup (13) cm sup (-2) which is deposited during growth interruption by MBE. Transistor structures exhibit DC current gains up to 1000. The effective base transit time is negligible in these transistors and it is postulated that very high speed non-equilibrium transport may occur in the collector region.