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.     

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     

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     

共振隧穿二极管的设计和研制

用分子束外延在半绝缘砷化镓上生长两垒一阱结构,制成RTD单管。经过材料生长设计、工艺设计和版图设计几方面的改进,测得最高振荡频率已达54GHz。     

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     

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     

Pspice resonant tunneling diode models and application circuits

Using the analogue behavioural modelling capabilities of Pspice, the current–voltage characteristics and the large-signal equivalent circuit of a resonant tunneling diode are exploited to create a Pspice compatible model for the diode. The model is used, with very few other components, in the simulation of a number of circuit applications, including a sinusoidal wave generator, a frequency multiplier and three state logic circuits. The simulated circuit details, the related waveforms and three-state logic operations are described. The circuits are characterized mainly by their reduced complexity and ease of analysis.     

Integration of a resonant tunneling diode and an optical communications laser

We report on the first integration of a resonant tunneling diode and an optical communications laser operating at around 1.5 /spl mu/m. We demonstrate its low-frequency bistable operation and model its electrical characteristics.     

Design of nanopipelined adder based on resonant tunneling diode

Due to the negative differential resistance exhibited by resonant tunneling diode (RTD), RTD is suited to implement the threshold gates and increases the functionality of a single gate. Recently, multi-threshold threshold gates (MTTGs) and generalized threshold gates (GTGs) have been proposed, which extend the circuit applications of RTDs. In this paper, a new RTD full adder structure with three logic modules is proposed. Based on this structure, four different adders are built with the combination of different module circuits based on MTTG and GTG. From the simulation results, one of the proposed circuits with GTG structure, namely FA_GG, has the best performance, which reduces 27.7–45.9% power-delay product value in comparison with the previous designs.     

Double-barrier resonant tunneling transport model

A semiquantum transport model for electron transport in the resonant tunneling diode (RTD) is presented. The total electrons tunneling through the RTD are partitioned into two parts. The first is the coherent tunneling electrons, which do not experience any scattering except by the barriers during tunneling. These electrons are described by the damped resonant tunneling model. The second is the incoherent tunneling electrons, which are the electrons scattered in the quantum well by the phonons, impurities, etc. The hot electron distribution, which is characterized by the effective Fermi energy μ_e and electron temperature T_e, is proposed to model the nonequilibrium distribution of the incoherent electrons in the well. The parameters μ_e and T_e can be uniquely determined by applying the energy conservation law and the particle conservation law to the incoherent electrons in the well. The incoherent electrons play a major role in the operation of the RTD. The capacitance of the RTD is investigated, based on the model and Poisson's equation. Extensive numerical results are presented     

Multibit resonant tunneling diode SRAM cell based on slew-rateaddressing

We propose and demonstrate a resonant-tunneling diode (RTD) based memory cell in which N bits are stored in a series combination of N RTDs without internal node contacts. The slew rate of an applied voltage signal determines the circuit switching dynamics and allows addressing of the bits. We verify slew rate dependent switching order of up to four series RTDs experimentally and through SPICE simulation incorporating a physics-based RTD model. The new addressing scheme allows N bits to be stored in a stack of N vertically integrated RTDs compared to log₂ (N) bits in previous demonstrations. We demonstrate a two-bit two-RTD static memory cell based on the new method     

Self-consistent transit-time model for a resonant tunnel diode

We present a self-consistent compact model for the small-signal impedance of a resonant tunnel diode (RTD) with a finite collector transit time. The effect of the collector transit time on the device impedance is described for three In/sub 0.53/Ga/sub 0.47/AsAlAs-InAs RTDs with current densities ranging from 14 kA/cm/sup 2/ to 570 kA/cm/sup 2/ with various collector spacer lengths for dc biasing in both the positive and negative differential resistance regions.     

A Wigner function-based quantum ensemble Monte Carlo study of a resonant tunneling diode

We present results of resonant tunneling diode operation achieved from a particle-based quantum ensemble Monte Carlo (EMC) simulation that is based on the Wigner distribution function (WDF). Methods of including the Wigner potential into the EMC, to incorporate natural quantum phenomena, via a particle property we call the affinity are discussed. Dissipation is included via normal Monte Carlo procedures and the solution is coupled to a Poisson solver to achieve fully selfconsistent results.     

A multiple-state memory cell based on the resonant tunneling diode

The device consists primarily of several molecular-beam-epitaxy (MBE-) grown GaAs/(AlGa)As resonant tunneling diodes connected in parallel. This device exhibits multiple peaks in the I-V characteristic. When a load resistor is connected, the circuit can be operated in a multiple stable mode. With this concept, implementation of three-state and four-state memory cells are made. In the three-state case the operating points at voltages V₀=0.27 V , V₁=0.42 V, and V₂=0.53 V represent the logic levels 0, 1, and 2. Similarly for the four-state memory cell the logic levels voltages are V₀=0.35 V, V₁=0.42 V, V₂=0.54 V, and V ₃=0.59 V. A suggestion of an integrated device structure using this concept is also presented     

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     

Optical control of resonant tunneling diode monolithically integrated with PIN photodiode

Optical control of the resonant tunneling characteristics of an integrated optoelectronic device with a monolithic integrated double-barrier/PIN structure is studied. Optical switching of the bistable resonant tunneling state and optical injection locking of a resonant tunneling oscillator at 1 GHz are demonstrated.     

Experimental demonstration of single peak IV characteristics in anovel resonant tunneling diode

Single peak IV characteristics are experimentally demonstrated by a novel resonant tunneling diode, a resonant tunneling pinch-off diode (RTPD), specially designed to make the coupling between the pinch-off effect and the resonant tunneling effect in the diode itself effective. RTPDs were fabricated using the InGaAs-AlAs-InAlAs material system grown by MBE on semi-insulating InP substrate. Device parameter (emitter width and collector thickness) dependence of the IV characteristics is investigated and compared with previously reported theory. Good agreement between them confirms that the mechanism that brings about the novel characteristics in the RTPD is the above mentioned coupling, and gives guidelines for achieving an RTPD with ideal single peak IV characteristics     

器件模拟对AlGaAs/GaAs RTD的特性分析(英文)

使用SILVACO公司的器件模拟软件ATLAS对AlGaAs/GaAs共振隧穿二极管(RTD)进行了器件模拟,得到了不同结构的RTD的I-V特性曲线。对量子阱宽度、掺杂浓度、势垒宽度和高度对RTD的I-V特性的影响进行了详细的分析。     

Effect of radial growth rate variation on resonant tunneling diode current-Voltage characteristics

The uniformity of electronic device characteristics is dependent on the uniformity of the epitaxial material. Uniformity is particularly important for resonant tunneling diodes where small changes in well or barrier thickness can have profound effects on the diode current-voltage characteristics. The variability of these characteristics due to growth rate nonuniformity for epitaxial structures grown by molecular beam epitaxy has been documented and the magnitude of the thickness variations analyzed using photoluminescence and a theoretical model. An increase of 17 meV was observed in the quantum well ground state, corresponding to a 15% thinning of the well from the center to the edge of the substrate.     

Analysis of resonant tunneling using the equivalenttransmission-line model

Presents a simple general and exact method for solving resonant tunneling problems in multilayered heterostructures. This method is based on the analogy of wave propagation between the transmission line and the potential structure. By using the proposed method, it is shown that electron wave propagation can be treated as wave propagation on an equivalent circuit and that various problems can be systematically solved by using well-developed circuit functions and circuit matrixes. In particular, our equivalent circuit can be effectively used for analysis of resonant interband tunneling (RIT) structures and resonant tunneling structures including Γ-X mixing by using the interface matrix. Various properties of the resonant tunneling structure and a guideline for designing new quantum effect devices can be easily obtained. In order to show the validity and usefulness of this method, some numerical examples of InAs-GaSb and GaAs-AlAs potential barrier structures are presented