Variable lateral quantum confinement transistor

Abstract

A quantum interference device in the form of a variable lateral confinement resonant tunneling transistor having a quantum waveguide structure including a primary current transmission path defined by a region between source and drain electrodes and where there is a resonance region therebetween in which quantum interference of tunneling wave functions establish a resonance tunneling condition that extends beyond the primary current path. Upon the application of a voltage across the drain and source electrodes, a tunneling current can be made to flow. A gate electrode formed on the quantum well structure remote from the primary current transmission path includes a variable depletion region thereunder or an electrostatic pinch off region, the size of which is a function of the magnitude of the bias voltage applied thereto. The size of the depletion region or the pinch off region affects the dimensions of the resonance region and accordingly the current flow between the source and drain electrodes as a result of a change in the energy and momentum conditions for resonance tunneling.

What is claimed is: 
     
       1. A quantum interference device, comprising: a semiconductor quantum waveguide structure comprising a primary current transmission path disposed between source and drain electrodes; a resonance region disposed between the source and drain electrodes and in the primary current transmission path, wherein the resonance region includes a quantum well and tunneling barrier regions disposed on opposite sides of the quantum well, wherein the resonance region is disposed within the primary current transmission path so as to form a quantum tunneling resonator; and a current control electrode located on said quantum waveguide structure remote from said primary current transmission path, said control electrode comprising a gate electrode, wherein a bias voltage is applied to the gate electrode which causes a change in dimensions of said resonance region and thereby changes in the current flow between said current carrying electrodes occur as a result of a change in the resonance tunneling and wherein said source, drain, quantum well, and barrier regions are smaller in width than the coherence length of the electron wave function.   
     
     
       2. The device of claim 1 wherein said source and drain electrodes include semiconductor source and drain regions adjacent said barrier regions and respective metal contacts on said source and drain regions, and wherein the gate electrode includes a metal contact on said quantum well region. 
     
     
       3. The device of claim 2 wherein said device comprises a planar type transistor, where said quantum well and said source and drain electrodes comprise regions of GaAs and said barrier regions are comprised of AlGaAs. 
     
     
       4. The device of claim 3 wherein said device further comprises a GaAs substrate with an AlGaAs isolation layer. 
     
     
       5. The device of claim 2 wherein said device comprises an epilayer type transistor structure and where said quantum well resonator region is comprised of a layer of GaAs, said barrier regions are comprised of layers of AlGaAs and said source and drain regions are comprised of layers of n-GaAs. 
     
     
       6. The device of claim 1 wherein said device is fabricated from material selected from Group III-V compounds. 
     
     
       7. The device of claim 6 wherein said source and drain regions are mutually aligned in a first direction and said quantum well resonator region extends outwardly from between said source and drain regions in a second direction. 
     
     
       8. The device of claim 7 wherein said gate electrode is located on a surface of said resonance region layer which is common to a barrier layer adjacent the source region layer. 
     
     
       9. A quantum interference device, comprising: a semiconductor quantum waveguide structure comprising a primary current transmission path disposed between source and drain electrodes; a resonance region disposed between the source and drain electrodes and in the primary current transmission path, wherein the resonance region includes a quantum well and tunneling barrier regions disposed on opposite sides of the quantum well, wherein the resonance region is disposed within the primary current transmission path so as to form a quantum tunneling resonator; and a current control electrode located on said quantum waveguide structure remote from said primary current transmission path, said .control electrode comprising a gate electrode, wherein a bias voltage is applied to the gate electrode which causes a change in dimensions of said resonance region and thereby changes in the current flow between said current carrying electrodes occur as a result of a change in the resonance tunneling and wherein said source, drain, quantum well, and barrier regions are smaller in width and length than the coherence length of the electron wave function.