Modulation of space-charge-limited current flow in insulated-gate field-effect tetrodes

The electrical characteristics of n-channel depletion-type and p-channel enhancement-type space-charge-limited tetrodes are presented. The devices are derived from the MOSFET structure and are fabricated on nearly intrinsic silicon substrates with very small channel lengths. In both structures, the current flowing between drain and source can be modulated by either of two high-impedance control terminals. The dominant conduction mechanism is space-charge-limited current flow, and the observed current-voltage characteristics of each device follow the Mott and Gurney relationship at high current levels.