Negative Resistance Field-effect Transistor Research Articles

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

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.

Ultrahigh and controllable drain current peak-to-valley ratio in negative resistance field-effect transistors with a strained InGaAs channel

Negative resistance field-effect transistor (NERFET) devices using either strained InGaAs or unstrained GaAs channel layers have been fabricated. The strained InGaAs channel NERFET's show strong negative differential resistance and large drain current peak-to-valley ratio. The peak-to-valley ratio of the InGaAs channel NERFET is more than 3000 at room temperature and larger than one million (10/sup 6/) at 77 K. The peak-to-valley ratio is controllable by adjusting the collector voltage.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

High performance three-terminal δ-doped GaAs negative resistance field-effect transistor based on real-space transfer

A three-terminal delta -doped GaAs real-space transfer transistor has been demonstrated by low-pressure metal organic chemical vapour deposition for the first time. The device has the advantages of: ease of growth and fabrication, large and adjustable peak-to-valley current ratio even at room temperature, extremely sharp charge injection, high transconductance, and high-power handling capability.

AlGaAs/GaAs charge injection transistor/negative resistance field-effect transistor fabricated with shallow Pd/Ge ohmic contacts

AlGaAs/GaAs charge injection transistor (CHINT)/negative resistance field-effect transistor (NERFET) devices are fabricated with Pd/Ge ohmic contacts. Pd and Ge are deposited by e-beam evaporation. The contact metal layers are annealed by rapid thermal annealing at 450–500 °C for 1 min. This gives a shallow ohmic contact and low specific contact resistivity. The better ρc are on the order of 10−6 Ω cm2. Using Pd/Ge contacts and rapid thermal annealing method, the metallization of CHINT/NERFET becomes much less critical. Good device performance under NERFET mode and CHINT mode is achieved. The largest peak-to-valley ratio of NERFET is about 15 at room temperature. The process developed in this work considerably simplifies the fabrication of CHINT/NERFET devices.

P-channel negative resistance field-effect transistor

We experimentally demonstrate the first p-channel negative resistance field-effect transistor. Low-temperature current-voltage characteristics exhibit negative differential resistance in the drain circuit which is controlled by the substrate voltage. The negative differential resistance is attributed to the real-space transfer of holes.

Strained layer AlGaAs-GaAs-InGaAs real-space transferred electron devices

Experimental results of two AlGaAs-GaAs real-space transferred electron devices, the negative resistance field-effect transistor and charge-injection transistor, which incorporates a strained layer In0.22Ga0.78As channel are reported. The negative differential resistance in the drain circuit has a drain current peak-to-valley ratio of more than 1200 at room temperature.

New features of real-space hot-electron transfer in the NERFET

We report two new effects of negative differential resistance in the modulation doped AlGaAs/GaAs Negative Resistance Field Effect Transistor. Both effects are well controlled by a third electrode. Presence of a top n + AlGaAs layer causes a hot-electron real-space transfer to this layer and prevents the electron transfer to the collector. Creation of the high-field domain in the source-drain channel is needed to activate the the hot-electron injection to the collector. The real-space transfer to the top n + AlGaAs layer combined with the quenching of the high-field domain by the collector bias are responsible for the appearance of the observed new negative differential resistance effects.

New negative differential resistance effects in the negative resistance field-effect transistor

We report two new effects of negative differential resistance in the modulation-doped AlGaAs/GaAs negative resistance field-effect transistor. Both effects are well controlled by a third electrode. Presence of a top n+ AlGaAs layer causes a hot-electron real-space transfer to this layer, and prevents the electron transfer to the collector. Creation of the high-field domain in the source-drain channel is needed to activate the hot-electron injection to the collector. The real-space transfer to the top n+AlGaAs layer, combined with the quenching of the high-field domain by the collector bias, are responsible for the appearance of the observed new negative differential resistance effects.

Strained layer InGaAs channel negative-resistance field-effect transistor

We report experimental results on a negative-resistance field-effect transistor (NERFET), grown by metalorganic chemical vapor deposition, which incorporates a strained In0.18Ga0.82As channel layer adjacent to the barrier. The thin InGaAs layer provides higher mobility and enhanced carrier confinement for the channel electrons. This device structure yields a significant increase in the drain current peak-to-valley ratio over comparable GaAs-AlGaAs NERFETs.

Theory of hot-electron injection in CHINT/NERFET devices

We have considered theoretically the basic physical processes underlying the operation of the charge injection transistor (CHINT) and the negative resistance field-effect transistor (NERFET). Our treatment is based on the electron temperature (T e ) approximation for the energy distribution of hot electrons in the two-dimensional electron gas (2DEG) channel. The T e is determined from an energy-balance equation which includes the following processes: 1) electron heating by the source-drain electric field (assumed uniform), 2) energy losses due to the interaction with phonons, 3) energy losses due to the emission of hot electrons from the channel into the second conducting layer (collector) and the attendant nonconservation of the channel current. Our theory gives a semi-quantitative analytical description of the current-voltage characteristics of CHINT/NERFET devices. Most--but not all-- of the important experimental features of the device operation are adequately described. Further improvement of the theory should include a realistic description of the field nonuniformity along the channel.

Negative-resistance field-effect transistor grown by organometallic chemical vapor deposition

Results of studying the process of real space hot electron transfer in the Negative-Resistance Field-Effect Transistor (NERFET) grown by organometallic chemical vapor deposition (OMCVD) are presented. In the modified AlGaAs/GaAs heterostructure we obtain a significant reduction in the parasitic leakage and a drastic improvement of negative differential resistance (NDR) in the drain circuit—with the peak-to-valley current ratio as high as 160 at room temperature. The effect of NDR is proved to be due to real-space transfer of hot electrons from the high mobility channel into the second conducting layer, with the current of transferred electrons depending exponentially on the second conducting layer potential. Analysis shows that the same device can operate as a Charge-Injection Transistor with an available power gain of about 5.

Silicon processing with silicon carbide furnace components : Bryan D. Foster and R. E. Tressler. Solid St. Technol. 143 (October 1984)

We report two new effects of negative differential resistance in the modulation doped AlGaAs/GaAs Negative Resistance Field Effect Transistor. Both effects are well controlled by a third electrode. Presence of a top n+ AlGaAs layer causes a hot-electron real-space transfer to this layer and prevents the electron transfer to the collector. Creation of the high-field domain in the source-drain channel is needed to activate the the hot-electron injection to the collector. The real-space transfer to the top n+ AlGaAs layer combined with the quenching of the high-field domain by the collector bias are responsible for the appearance of the observed new negative differential resistance effects.

Microwave generation in NERFET

Microwave generation in a NEgative Resistance Field-Effect Transistor (NERFET) is reported for the first time. This device is based on a GaAs/AlGaAs heterostructure which exhibits negative differential resistance due to a transfer of hot-electrons out of a source-drain channel and into a conducting substrate. In an untuned microwave circuit at 77 K, the NERFET was found to generate wide-band noise at frequencies up to 2.3 GHz. In a tunable resonant circuit, stable microwave oscillations were observed at frequencies as high as 1.45 GHz. While further experiments are needed to determine the performance limits of the NERFET, the preliminary results presented here demonstrate the potential of this new device as a high-frequency element.