DC and AC Characteristics of GaAs/InGaAs/AIGaAS Real Space Transfer Transistors

H C Chen

doi:10.1155/1998/95230

Abstract

DC and AC performances of a GaAs/InGaAs/AIGaAs negative resistance field-effect transistor (NERFET) are demonstrated by molecular beam epitaxy (MBE) for the first time. The negative differential resistance (NDR) resulted from the observation of the hot electron real space transfer effect in InGaAs channel. By Hall measurements, the structure shows carrier mobility as high as 4300 (13500) cm2/v-s at 300 (77)K, which is suitable for high frequency operation. For DC performance, the largest peak-to-valley current ratio of the device is about 5 at room temperature. For AC performance, S-parameter measurements of high frequency and microwave characteristics indicate a projected maximum frequency of oscillation offmax⁡=2.7GHzand a current gain cutoff frequency (fT) occurs at 1.8GHz.

Highlights

Negative resistance field-effect transistors (NERFET) are a three-terminal transistor based on the effect of real space transfer (RST) of hot electrons, When the heating voltage, VDS, is applied between source and drain electrodes, the emitter electrons are accelerated and become hot
(b) FIGURE (a) Schematic cross-section of GaAs/InGaAs/A1GaAs RST transistor (b) Energy band-diagram of the device show that the structure is suitable for high frequency and high power operations
In the negative differential resistance (NDR) region, the ID shows step-like changes with sudden drop in current

Summary

INTRODUCTION

Negative resistance field-effect transistors (NERFET) are a three-terminal transistor based on the effect of real space transfer (RST) of hot electrons, When the heating voltage, VDS, is applied between source and drain electrodes, the emitter electrons are accelerated and become hot. If bias is sufficiently large, electrons may have enough energy to spill over the potential barrier and transfer to the collector (substrate) terminal. The device exhibits an NDR in the source-drain and an efficient control of the injection current by the drain voltage.. Finding the small-signal circuit and frequency characteristics in order to improve device performance. We use GaAs/InGaAs/A1GaAs-based material to characterize the DC and AC performances of RST. The use of InGaAs channel provides potential applications for optoelectronic integrated circuits and high-speed microwave devices in light of its F-to-L valley separation, high mobility, and large peak electron velocity

EXPERIMENTAL

RESULTS AND DISCUSSION

CONCLUSIONS