CHARGE-TRANSFER LIMITATIONS IN DELTA-DOPED ALGAAS/INGAAS PSEUDOMORPHIC HIGH-ELECTRON-MOBILITY TRANSISTORS

The charge transfer between the δ-doped region and channel of an AlxGa1-xAs/InyGa1-yAs pseudomorphic high electron mobility transistor (p-HEMT) is explored theoretically. The model is based on a self-consistent solution of the kp Hamiltonian and Poisson equation and explicitly accounts for surface states. It is shown that heavily doping the δ layer does not guarantee a large amount of electrons in the channel. At higher doping, an increasing number of electrons are retained in the δ-layer, reducing the charge-transfer ratio. It is further shown that charge transfer is drastically reduced when the cap layer is recessed to form the gate. © 1995 American Institute of Physics.