Self-Aligned AlGaAs/GaAs HBT's with Tungsten N and P Type Ohmic Contacts

A self-aligned GaAlAs/GaAs HBT technology with tungsten emitter and base ohmic contacts is presented. The HBT's layers are grown by MBE, the emitter contact layer is Ga
0.35
In
0.65
As. A Zinc diffusion allows for contacting the extrinsic base layer. Self-alignment is obtained by the diffusion around the emitter mesa; nitride spacers are used to isolate the intrinsic area during the diffusion process.