A study of resonant tunneling in a 3-terminal ballistic device

Preliminary results are presented for a 3-terminal device fabricated by incorporating a narrow quantum well into the collector barrier of a unipolar hot electron transistor. The structure allows unique studies of the mechanism of resonant tunneling in which the carrier injection energy and the bias across the double barrier can be independently varied. The transistor clearly shows an additional current collection threshold representing as much as 10% of the injected current attributable to tunneling via the single subband in the quantum well. This interpretation is confirmed by measurements in perpendicular and parallel magnetic fields despite the fact that theoretical estimates of the resonant tunneling current without scattering are many orders of magnitude smaller, and there are strong indications that elastic scattering in the well is responsible for the enormous discrepancy. The data tend to support proposals (Guéret, 1989a, 1989b; Wolak, 1988) that elastic scattering is responsible for the large valley currents in resonant tunneling diodes, and it appears that the tunnel process may not be completely incoherent as has frequently been assumed up to now.     

Monolithic AlAs-InGaAs-InGaP-GaAs HRT-FETS with PVCR of 960 at 300 K

This letter reports the significant N-shaped negative-differential resistance characteristics with three-terminal controllability of a monolithic heterostructure resonant tunneling field-effect transistor, realized by integrating the AlAs-In/sub 0.25/Ga/sub 0.75/As-AlAs double-barrier single-well resonant tunneling (RT) structure into the drain regime of the In/sub 0.49/Ga/sub 0.51/P-In/sub 0.25/Ga/sub 0.75/As-GaAs /spl delta/-high-electron mobility transistor. A peak-to-valley current ratio in excess of 960 at room temperature has been demonstrated, with a peak current density (J/sub p/) of 50.6 mA/mm, and a valley current density (J/sub v/) of 52.7 /spl mu/A/mm, respectively, with a transistor gate length of 1.0 /spl mu/m. The maximum current drive density was observed to be 478 A/mm-cm/sup 2/.     

Frequency multipliers using InP-based resonant-tunneling highelectron 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     

InGaAs resonant tunneling transistors using a coupled-quantum-wellbase with strained AlAs tunnel barriers

A bipolar-type resonant tunneling transistor is studied of which the base is identical to a coupled quantum well. On the basis of the InGaAs material system strained AlAs tunnel barriers and a graded InGaAlAs emitter are used. Molecular beam epitaxy growth conditions are studied, showing a specific influence of growth temperature and arsenic pressure. We find clear evidence for resonant tunneling: a saturation of the collector current and a maximum of the transconductance with increasing base-emitter bias in a three-terminal transistor structure. A corresponding effect in a phototransistor structure is found as a maximum of differential current gain with increasing incident light intensity. Room temperature and low temperature (80 K) high-frequency properties are determined and are used to estimate the resonant tunneling time     

Resonant tunneling permeable base transistors with high transconductance

A GaAs-based resonant tunneling permeable base transistor has been developed and evaluated at room temperature. The transistor is fabricated by overgrowing a tungsten gate placed next to an AlGaAs-GaAs-InGaAs resonant tunneling heterostructure. By changing the gate voltage, the effective conducting area of the tunnel diode can be modulated and the collector-emitter current thus controlled. Peak currents above 300 mA/mm and a maximum transconductance of 270 mS/mm have been obtained.     

Quantum distributed model of the resonant tunneling transistor

Two-dimensional simulation is crucial in the analysis of the transport characteristics of a resonant tunneling transistor that has a base electrode attached to the well region of a double barrier structure because of the transistor's two-dimensional heterogeneousness. We propose a novel numerical model of the resonant tunneling transistor that includes two-dimensional potential distribution and two-dimensional spatial current distribution. By using this mode in the present model, it is found that the transistor's I-V characteristics are strongly dependent on its internal well resistance     

Clear negative characteristics observed in coupled-quantum-wellbase resonant tunneling transistors

Clear negative resistance characteristics observed in a resonant tunneling transistor with a coupled-quantum-well (CQW) base are reported. The collector current reveals negative resistance properties with respect not only to the base-emitter voltage but also the base current in the common-emitter configuration. The collector current peak-to-valley ratio is enhanced in the CQW-base transistor compared with a reference transistor with a single-quantum-well (SQW) base     

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     

Parallel Adder Design with Reduced Circuit Complexity Using Resonant Tunneling Transistors and Threshold Logic

Quantum-effect devices utilizing resonant tunneling are promising candidates for future nano-scale integration. Originating from the technological progress of semiconductor technology, circuit architectures with reduced complexity are investigated by exploiting the negative-differential resistance of resonant tunneling devices. In this paper a resonant tunneling device threshold logic family based on the Monostable-Bistable Transition Logic Element (MOBILE) is proposed and applied to different parallel adder designs, such as ripple carry and binary carry lookahead adders. The basic device is a resonant tunneling transistor (RTT) composed of a resonant tunneling diode monolithically integrated on the drain contact layer of a heterostructure field effect transistor. On the circuit level the key components are a programmable NAND/NOR logic gate, threshold logic gates, and parallel counters. The special properties of MOBILE logic gates are considered by a bit-level pipelined circuit style. Experimental results are presented for the NAND/NOR logic gate.     

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     

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.     

Resonant tunneling transistor lasers: A new approach to obtain multi-state switching and bistable operation

Bipolar resonant tunneling heterotransistor structures, which can be configured to operate as multi-state or as bistable lasers, are described. Both edge and surface-emitting structures are presented. Computations of various optoelectronics parameters including confinement factor, threshold current density, and cavity modes for a stripe-geometry structure are presented. In addition, simulations of base and collector currents are given for a resonant tunneling transistor to demonstrate the feasibility of lasing in the base region.     

Realization of a resonant tunneling permeable base transistor withoptimized overgrown GaAs interfaces

A resonant tunneling permeable base transistor has been realized experimentally by overgrowing a tungsten grating placed in direct vicinity to a double barrier heterostructure. In this way, we can directly modulate the tunneling current via an embedded gate. Since the quality of the overgrown interface is critical, special attention is paid to this issue, and the effect of different wet etchants prior to overgrowth is studied both by electrical measurements and by the use of an atomic force microscope. A clear dependence of the electrical properties and the crystal quality on the etchants used is found. This is a key result for the realization of our resonant tunneling device     

肖特基栅型共振隧穿晶体管的制作研究

已研制成了肖特基栅共振隧穿晶体管,在双势垒结构上蒸发铂金形成栅。通过调制准二维电子积累层的面积进而达到控制隧穿电流的目的。并对发射极正反接电压不同而出现的不同调制现象进行了分析。     

Quantum transistors and circuits break through the barriers

Resonant tunneling diodes and transistors, which are `vertical' quantum devices, in which the current flows perpendicular to the layers instead of along them, are discussed. The operation of both devices is explained. Various types of resonant tunneling transistor are examined, with particular attention to multistate devices. Applications to frequency multipliers, parity generators, and analog-to-digital converters are presented     

新型电子器件和光学器件的共振隧穿结构

描述了一种新型共振隧穿结构器件，这种器件包含了通过可变间隙超晶格能量滤波器（ＶＳＳＥＦ）中的耦合量子附态的隧穿过程．论证了通过ＡｌＡｓ／ＧａＡｓＶＳＳＥＦ器件高能态和ＡｌＧａＡｓ／ＧａＡｓ超晶格受激态的共振隧穿，描述了这种器件作为较高功率微波源和共振隧穿晶体管的应用，并讨论了共振隧穿结构作为雪崩探测器和红外发射器等光学器件的潜在应用．     

纳米电子器件-高峰值峰谷电流比InP基共振隧穿二极管的实现

利用分子束外延技术研制出InP基IhAs/In0.53Ga0.47As/AlAs共振隧穿二极管,其中势垒为10个单分子AlAs,势阱由8个单分子层In0.53Ga0.47As阱和4个单分子层InAs子阱组成.室温下峰值电流密度接近3kA/cm2,峰和谷的电流密度比率达到19.     

A model for the resonant tunneling semiconductor-controlled rectifier

A new switch called a resonant-tunneling-semiconductor-controlled rectifier (RT-SCR) has been proposed. A two-transistor model is used for the device. One of the transistors in the two-transistor model is assumed to be a resonant tunneling transistor (RTT), while the other transistor is taken to be a bipolar transistor. The current–voltage relationships of the device have been numerically obtained and compared with the traditional thyristor characteristics. The new device requires smaller turn-on gate voltage than a comparable traditional device for the same gate current. This indicates that in comparison with the traditional thyristor, a smaller control current may be used to turn on the device at a particular voltage.     

Novel resonant tunneling transistor with high transconductance atroom temperature

A resonant tunneling transistor (RTT) utilizing a novel heterodimensional Schottky gate technology is described. The gate is formed by electroplating Pt/Au onto the side of an AlGaAs/GaAs double barrier structure. The gate voltage modulates the drain current by modulating the area of the quasi-two dimensional electron accumulation layer which forms above the source barrier under drain-source bias. Room temperature transistor characteristics included a peak current of 225 mA/mm and peak transconductance of 218 mS/mm. The ultrafine fabrication process is also discussed     

晶体管的新概念

简要介绍了几种晶体管,包括柔性晶体管、单原子晶体管、单电子晶体管、单自旋晶体管、量子力学晶体管、谐振隧穿晶体管、薄膜晶体管、透明晶体管和纳米晶体管的新概念。