Two-band combined model of a resonant tunneling diode

A two-band combined model of a resonant tunneling diode, based on the semiclassical and quantum mechanical (the wave function formalism) approaches is proposed. The main specific feature of this model is the possibility of taking into account the interaction between different classical or quantum mechanical device regions with simultaneous consideration of the Γ-X intervalley scattering. It is shown that this model gives satisfactory agreement with the experimental data on the current-voltage characteristics and allows explanation of the plateau region in these characteristics within the stationary model.     

Zero bias resonant tunnel Schottky contact diode for wide-band direct detection

A Schottky-collector resonant tunnel diode detector has been fabricated and characterized at zero bias up to 400 GHz. General device structure and fabrication are discussed, and small-signal equivalent models are presented for different diode areas. Over the measured range of 200 to 400 GHz using a monolithic antenna structure, noise equivalent power values between 3-8 pW/Hz/sup 1/2/ are achieved. The current-voltage characteristics of the diode show weak temperature dependence over a measured range of 213-323 K.     

Unified AC model for the resonant tunneling diode

A physics-based model is shown to yield the small-signal equivalent circuit of the resonant tunneling diode (RTD) including an analytic expression for both the quantum inductance and capacitance. This model unifies previous models by Brown et al. for quantum inductance and by Lake and Yang for quantum capacitance, and extends the RTD SPICE model of Broekaert. The equivalent circuit has been fit to both current-voltage and microwave S-parameter measurements of AlAs-InGaAs-InAs-InGaAs-AlAs RTDs from 45 MHz to 30 GHz and over biases from 0 to 0.81 V. Good agreement between the model and measurement is shown.     

Monolithic Schottky-collector resonant tunnel diode oscillatorarrays to 650 GHz

We report monolithic array oscillators incorporating Schottky-collector resonant tunnel diodes (SRTD's). In the SRTD, a 0.1-μm width Schottky collector contact provides a greatly reduced device series resistance, resulting in an estimated 2.2 THz maximum frequency of oscillation. A 64-element oscillator array oscillated at 650 GHz while a 16-element array produced 28 μW at 290 GHz     

Subharmonic mixer with improved intermodulation characteristics based on a resonant tunnel diode

A comparative analysis of the operation of subharmonic mixers (SHMs) based on a resonant tunnel diode (RTD) and a Schottky-barrier diode (SBD) is performed. The dependences of the conversion loss of the RTD- and SBD-based SHMs on local-oscillator power are calculated. The SHM operation modes that allow the performance indices of the RTD-based mixer to be improved as compared to those of the SBD-based mixer are presented. The possibility of increasing the upper intermodulation-distortion dynamic-range limit of the RTD-based SHM as compared to that of the SBD-based SHM is theoretically shown and experimentally confirmed.     

An improved multipeak resonant tunneling diode model for nine-stateresonant tunneling diode memory circuit simulation

A simple Spice equivalent circuit model for simulating current-voltage (I-V) characteristics and logic operation waveforms of an eight-peak resonant tunneling diode is presented. The simulated results agreed well with experimental data measured from an eight-peak resonant tunneling diode device fabricated by Seabaugh's experiment. This is shown through PSpice simulation     

Direct optical frequency modulation and injection locking of resonant tunnel diode oscillator

Preliminary results indicate that a resonant tunnel diode (RTD) oscillator can be optically tuned, frequency modulated, and injection locked. Experiments were performed in which a 2.8 GHz RTD oscillator was frequency modulated from DC to 100 MHz and injection locked over a 150 kHz bandwidth with a laser diode via fibre optics.<>     

Small signal equivalent circuit model for the metal-insulator-semiconductor tunnel diode

The small signal a.c. equivalent circuit technique is extended to deal with MIS diodes in which there may be considerable tunneling current. Exact a.c. equivalent circuit models are derived for metal-to-surface state tunneling and metal-to-semiconductor band tunneling. In addition, the proper admittance matrix node reduction process for pre-elimination of surface state nodes is given. This reduction process allows for a considerable simplification of the a.c. admittance problem.     

Nine-state resonant tunneling diode memory

The authors demonstrate an epitaxial series combination of eight pseudomorphic AlAs/In_0.53Ga_0.47As/InAs resonant tunneling diodes (RTDs) grown by molecular beam epitaxy on InP. This series RTD produces an eight-peak multiple negative differential resistance characteristic with a peak-to-valley current ratio (PVR) exceeding 2 per peak at a peak current density of approximately 6 kA/cm ². Hysteresis in the current-voltage characteristic is reduced by uniformly Si doping the double-barrier resonant tunneling region at a density of 5×10¹⁶ cm^-3. Using this multiple-peak RTD in series with a field-effect transistor load, a nine-state multivalued memory circuit is demonstrated     

A triple-well resonant tunneling diode for multiple-valued logicapplication

A resonant tunneling diode with four potential barriers and three quantum wells was fabricated and applied to multiple-valued logic. The diode exhibited significant double negative resistance characteristics and operated as a triple stable device with a single voltage between 180 and 230 K     

Theoretical study of a Gunn diode in a resonant circuit

A computer simulation of a GaAs Gunn diode in a parallel resonant circuit has been made to determine the optimum device and circuit parameters. The maximum dc to RF efficiency, 5 to 8 percent, is obtained when the product of doping and length is between 10¹²and 2 × 10¹²cm^-2, the product of frequency and length is 10⁷cm/s, and the bias voltage divided by length is 8000 V/cm for a load resistance of30 R_{0}where R0is the low-voltage resistance of the diode. The product of output power and load resistance varies with frequencyfasC f^{2}whereCis 12,000 watt-ohm-GHz²for a load resistance of50 R_{0}. The frequency can be varied over an octave tuning range by the resonant circuit.     

Noise considerations for a tunnel diode integrated rectangular patch antenna

The tunnel diode integrated rectangular patch antenna is investigated, with emphasis mainly on noise considerations. Noise power is calculated and is found to increase very slightly with frequency for both GaAs and Ge tunnel diode loaded patches. Noise figure and noise temperature also increase with frequency for GaAs and Ge tunnel diode loaded patches. Loading the patch with the tunnel diode increases the effective noise figure and effective noise temperature of the patch, degrading the performance of the communication system significantly.     

Frequency-stable tunnel diode oscillators

From a linear analysis of a tunnel diode loaded with a transmission line, it is shown that oscillations highly stable in frequency are possible. Preliminary experimental results are in agreement with the theory. Stability on the order of one part in 10/SUP 5/ is easily attained.     

Two-port noise and impedance measurements for two-terminal deviceswith a resonant tunneling diode example

A two-port technique is presented for determining the circuit elements and noise sources of the equivalent circuit of a two-terminal device at microwave frequencies. The two-terminal device is connected as a two-port so that intrinsic and parasitic circuit elements can be obtained from full two-port S-parameter measurements. This measurement does not require one of the two contacts to be grounded, which makes it particularly well suited for the characterization of integrated devices where parasitic elements become important and cannot be easily calculated. The noise of the device is measured by employing a noise-figure meter and the intrinsic noise is computed from the measured terminal noise. As an example, the impedance and noise elements of a resonant tunneling diode (RTD) are measured over frequency ranges of 2-8 and 2-4 GHz, respectively     

Switching-time statistics for a ramp-excited tunnel diode switch (Corresp.)

An analytical model is developed which yields switching-time jitter statistics for a tunnel diode excited by a current ramp. For appropriate wide-band noise, a "switch sensitivity period" is defined over which a weighted average (a stochastic integral)of the noise specifies the deviation in the switching time. The predictions agree with experimental results.     

Self-consistent modeling of resonant interband tunneling in bipolartunneling field-effect transistors

We present a model for the calculation of the tunneling current in resonant interband tunneling devices based on a transfer-Hamiltonian formalism. The model is fully self-consistent and includes electrons and both light and heavy holes. In particular, we show the viability of the bipolar tunneling field-effect transistor as a three-terminal multiple-NDR device with predicted currents reaching over 1000 A/cm² and theoretical peak-to-valley ratios up to 300     

Microwave detection using the resonant tunneling diode

An experimental and theoretical study in the use of a resonant tunneling diode (RTD) as a microwave detector, based on its small-signal equivalent circuit model, is presented. It is shown that the rectified current from the diode can be accurately predicted and that the diode can be operated as a reactive microwave detector which absorbs no microwave power. For this detection mode, a matching network which maximizes the applied AC voltage can be used