First Observation of Negative Differential Resistance in Surface Tunnel Transistors

Abstract

Negative differential resistance (NDR) due to an interband tunneling has been observed at room temperature for the first time in a Surface Tunnel Transistor (STT) under forward-bias conditions. To produce clear NDR characteristics, the electron density in the channel was designed to be high enough to induce band overlap at the channel/drain junction. In order to increase the tunneling current further, a channel doped structure, in which a thin n⁺-GaAs layer was inserted between a p⁺-GaAs layer (drain) and an i-GaAs layer, was proposed. This channel doped STT exhibited a peak current density of 8 µ A/µ m, which is 280 times larger than that of the conventional STT.