Fabrication of a new type of field-effect transistor using neutralisation of shallow donors by atomic hydrogen in n-GaAs (Si)

We describe a new process for the fabrication of GaAs field-effect transistors. This process is based on the neutralisation of shallow donors by atomic hydrogen diffused into a highly silicon-doped epilayer. This original process should be able to produce field-effect transistors with low access resistances. Better linearity and high breakdown voltage are expected owing to the active impurity gradient present in the hydrogenated layer. The first HFETs (hydrogenated FETs) show very encouraging characteristics. For a gate length of 1.2 ¿m their typical transconductance is 330 mS/mm and the cutoff frequency is larger than 15 GHz.