Characterization of Three-Terminal Junctions Operated as In-Plane Gated Field-Effect Transistors

The field-effect transistor operation of monolithic three-terminal junctions (TTJs) is demonstrated at room temperature. The TTJs are based on a modulation-doped GaAs/AlGaAs heterostructure with a 2-D electron gas situated 33 nm below the surface. By applying mask technology and wet chemical etching, several TTJs were fabricated, and the interplay between the TTJ geometry and the transistor characteristics is analyzed. For channel width smaller than 200 nm, drain currents of up to 9.3 muA and a maximum transconductance exceeding 15.7 muA/V are observed in the transfer characteristics. It is also demonstrated that engineering the channel and gate branch allows one to control the device currents and the threshold voltages over a wide range.

I. Introduction

In modern electronic circuits and logic gates, field-effect transistors are the state-of-the-art devices [1]. Driven by the ongoing miniaturization, structural parameters in the deep submicrometer regime were reached. With a further scaling down, the impact of quantum effects like tunneling or the quantum capacitance increases, and the characteristics of the device can alter significantly [2]. As a consequence, great effort is spent to utilize low-dimensional effects for the realization of nanoelectronic devices based on novel working principles, in which quantum effects lead to an improvement of the device behavior. Within this frame, three-terminal junctions (TTJs) have become subject of intense research activities, and stable rectification, due to the ballistic transport of electrons, has been observed [3]–[7]. Measurements on the frequency dependence of the rectification provided high-frequency functionality of up to several terahertz, which allows a large spectrum of applications [8]–[10]. Based on these findings, logic gates, a frequency multiplier, a ballistic half adder, and a set–reset latch have been demonstrated [11]–[15].