Room temperature operation of (Al,Ga,In)As/NiAl/(Al,Ga,In)As buried metal well hidden-field effect transistors

The realization of a buried metal electrode tunneling transistor is reported. The device is fabricated in an epitaxial monocrystalline (Al,Ga)As-NiAl-(Al,Ga)As semiconductor-metal-semiconductor heterostructure and uses the thinnest buried electrode ever reported. Using the current-voltage (I-V) characteristics of the Schottky diodes between the NiAl and the cladding semiconductor on either side, the 3.3-nm-thick buried metal is shown to behave as an independent electrode. The three terminal I-V results are used to describe the operation of a novel hidden-field effect transistor. A model for the transistor operation is proposed based on the resonant injection of hot carriers into a quantum confined subband of the buried metal well. This tunneling transistor operates at room temperature and exhibits a negative transconductance corresponding to approximately 0.5% of the total source current. The modulation mechanism requires stationary states and therefore is limited to the portion of the source current which is injected into the drain by resonant tunneling.<>