Resonant-tunneling High Electron Mobility Transistor Research Articles

Design and simulation of a novel GaN based resonant tunneling high electron mobility transistor on a silicon substrate

For the first time, we have introduced a novel GaN based resonant tunneling high electron mobility transistor (RTHEMT) on a silicon substrate. A monolithically integrated GaN based inverted high electron mobility transistor (HEMT) and a resonant tunneling diode (RTD) are designed and simulated using the ATLAS simulator and MATLAB in this study. The 10% Al composition in the barrier layer of the GaN based RTD structure provides a peak-to-valley current ratio of 2.66 which controls the GaN based HEMT performance. Thus the results indicate an improvement in the current–voltage characteristics of the RTHEMT by controlling the gate voltage in this structure. The introduction of silicon as a substrate is a unique step taken by us for this type of RTHEMT structure.

A New XOR Structure Based on Resonant-Tunneling High Electron Mobility Transistor

A new structure for an exclusive-OR (XOR) gate based on the resonant-tunneling high electron mobility transistor (RTHEMT) is introduced which comprises only an RTHEMT and two FETs. Calculations are done by utilizing a new subcircuit model for simulating the RTHEMT in the SPICE simulator. Details of the design, input, and output values and margins, delay of each transition, maximum operating frequency, static and dynamic power dissipations of the new structure are discussed and calculated and the performance is compared with other XOR gates which confirm that the presented structure has a high performance. Furthermore, to the best of authors' knowledge, it has the least component count in comparison to the existing structures.

A Monolithic Microwave-Integrated Circuit Doubler Using a Resonant-Tunneling High-Electron-Mobility Transistor

A resonant-tunneling high-electron-mobility transistor (RTHEMT) doubler with matching circuits is described. We obtained a large conversion gain even at low input power, which was due to the strong nonlinearity of the RTHEMT. The conversion gain was 1.5 dB for a -10 dBm input signal at 2.4 GHz. Power consumption was only 4 mW, which was one-fifth that of a doubler using a GaAs metal-semiconductor field effect transistor (MESFET). The maximum reflection loss was 6 dB at 2.4 GHz.

Large-signal microwave characteristics of resonant-tunneling high electron mobility transistors

The large-signal microwave characteristics of a resonant-tunneling high electron mobility transistor (RTHEMT) are investigated by experiments and simulations. A large number of harmonics, including extremely high-order harmonics with significant power, are observed in both the experiments and the simulations. The dependence of the output spectrum on input power shows that there is a critical input power for producing the extremely high-order harmonics, which is due to the bistability in the transfer characteristics. The origin of the bistability is explained by using an equivalent circuit model for the RTHEMT. Moreover, the dependence of the output power level of the low-order harmonics on input power was found to vary with the DC input voltage. This change of the dependence can be explained by examining the transfer characteristics. The DC transfer characteristics are the key to understanding the large-signal microwave characteristics peculiar to the RTHEMT.

Sampling phase detector using a resonant tunneling high electron mobility transistor for microwave phase-locked oscillators

A novel sampling phase detector (SPD) using a resonant-tunneling high electron mobility transistor (RTHEMT), which features strong nonlinear characteristics, is proposed and demonstrated as a means of achieving a simple, low-power-consumption SPD. We confirmed promising performance for an RTHEMT as a simple pulse generator in an SPD with low power consumption, even for a low reference-signal input level. An 11-GHz phase-locked oscillator is constructed along with the present SPD, and successfully phase-locked signals are obtained with it. These results clearly show the potential of constructing high-performance analog RF circuits based on RTHEMTs.

High-frequency small-signal and large-signal characteristics of resonant tunneling high electron mobility transistors (RTHEMTs)

High-frequency characteristics of a highly functional InP-based resonant-tunneling high electron mobility transistor (RTHEMT) are reported in this paper. Based on small-signal S-parameter measurement, a maximum current gain cutoff frequency f/sub T/ of 28.6 GHz and a maximum power gain cutoff frequency f/sub max/ of 90 GHz were obtained for an RTHEMT with a 0.7 /spl mu/m gate length. Large-signal characteristics are also reported, showing the potential of RTHEMT's for frequency multiplier applications featuring high-order harmonics multiplication with high conversion efficiency.

Frequency multipliers using InP-based resonant-tunneling high electron mobility transistors

Frequency multipliers (doubler and tripler) are demonstrated at room temperature, using a simple circuit that combines a load resistor with an InP-based resonant-tunneling high electron mobility transistor (RTHEMT). The RTHEMT incorporates an InGaAs/AlAs/InAs pseudomorphic resonant tunneling diode into the source of a nonalloyed ohmic contact InAlAs/InGaAs high electron mobility transistor. A nearly flat valley current is obtained in the RTHEMT's current-voltage characteristics, which results in pronounced negative transconductance throughout a wide range of drain-to-source bias voltages. As a result, frequency multipliers using RTHEMT's feature large output voltage swing and reduced power consumption.

Novel current–voltage characteristics in an InP-based resonant-tunneling high electron mobility transistor

We report novel current–voltage characteristics in an InP-based resonant-tunneling high electron mobility transistor (RTHEMT). This device incorporates a pseudomorphic InGaAs/AlAs/InAs resonant-tunneling diode into the source of a nonalloyed ohmic contact InAlAs/InGaAs high electron mobility transistor. Both pronounced negative differential resistance and negative transconductance are observed at room temperature. Most significantly, a near-flat valley current is obtained in the output current–voltage characteristics. This feature is achieved by the nonalloyed ohmic contact cap layer structure employed in the HEMT, which significantly reduces the parasitic resistance. The novel characteristics of RTHEMTs should lead to many attractive circuit applications.