Bipolar Field Effect Transistor Research Articles

The Bipolar Field-Effect Transistor: XIII. Physical Realizations of the Transistor and Circuits (One-Two-MOS-Gates on Thin-Thick Pure-Impure Base)

This paper reports the physical realization of the Bipolar Field-Effect Transistor (BiFET) and its one-transistor basic building block circuits. Examples are given for the one and two MOS gates on thin and thick, pure and impure base, with electron and hole contacts, and the corresponding theoretical current–voltage characteristics previously computed by us, without generation-recombination-trapping-tunneling of electrons and holes. These examples include the one-MOS-gate on semi-infinite thick impure base transistor (the bulk transistor) and the impurethin-base Silicon-on-Insulator (SOI) transistor and the two-MOS-gates on thin base transistors (the FinFET and the Thin Film Transistor TFT). Figures are given with the cross-section views containing the electron and hole concentration and current density distributions and trajectories and the corresponding DC current–voltage characteristics.

Improvement of Subthreshold MOSFET Characteristics Employing Field Effect Bipolar Transistor

A field effect transistor has the characteristic of high input resistance. Because a constant bias current is not necessary, it is widely utilized as a highly convenient element in existing integrated circuits. The exponential functional properties possessed by the bipolar transistor have the advantage of being able to realize large gain easily in comparison to the square power properties of the field effect transistor, but at present, the field effect transistor is used instead of the bipolar transistor. Amplifiers utilizing field effect transistors are inferior to those utilizing bipolar transistors from the standpoint of gain, output resistance, operational speed, etc.; consequently, in the next generation high speed communication technology, there is demand for an element that replaces the field effect transistor.This paper analyzes a subthreshold MOSFET employing Field Effect Bipolar Transistor (FEBT), which has high intrinsic gain and high input resistance, does not require a bias voltage at the signal input terminal, and can be used as a high-function field effect bipolar transistor capable of low power source voltage operations that solves the problems that have become topics in the large-scale integrated circuits of today.

The determination and importance of internal capacitances of transistors in the frequency band of commercial FM broadcasting

Using a single-capacitor Colpitts oscillator a method has been proposed for determination of internal capacitances of bipolar junction transistors (BJTs) and junction field effect transistors (JFETs) in the frequency band of commercial frequency modulation (FM) broadcasting. Variation of these capacitances with the operating bias point and the operating frequency of the active device has been considered. Practical implementation of this method does not require any unconventional measuring system. The changing behavior of the base-emitter capacitance of BJTs versus operating bias current has been utilized for designing a simple high-frequency amplitude-modulating (AM) system. This efficiently designed AM signal generator does not have any transformer and is an example showing the importance of internal capacitances of active devices.

Model generation of the silicon–germanium (Si1−xGex) bipolar inversion channel field effect transistor utilizing a two-dimensional device simulator

The development of an accurate model for an inversion base transistor in the bipolar inversion channel field effect transistor (BICFET) configuration is investigated in this report. Simulations were accomplished through the use of the Medici software, acquired from Avant! Corporation of Sunnyvale, California. This software, which is capable of modeling semiconductor devices comprised of conventional and/or user-defined materials, impurities, structures and operating conditions, was used to develop a model based on experimental device results from Stanford University.

GaN electronics for high power, high temperature applications

A brief review is given of recent progress in fabrication of high voltage GaN and AlGaN rectifiers, GaN/AlGaN heterojunction bipolar transistors and GaN metal-oxide semiconductor field effect transistors. Improvements in epitaxial layer quality and in fabrication techniques have led to significant advances in device performance.

Evidence of a thermally stable carbon-nitrogen deep level in carbon-doped, nitrogen-implanted, GaAs and AIGaAs

Nitrogen ion implantation is shown to form high resistivity regions (ps ≥ 1 × 1010 Ω/) in C-doped GaAs and Al0.35Ga0.65As that remains compensated after a 900°C anneal. This is in contrast to oxygen or fluorine implantation in C-doped GaAs which both recover the initial conductivity after a sufficiently high temperature anneal (800°C for F and 900°C for O). In C-doped Al0.35Ga0.65As N- and O-implant isolation is thermally stable but F-implanted samples regain the initial conductivity after a 700°C anneal. A dose dependence is observed for the formation of thermally stable N-implant compensation for both the GaAs and AIGaAs samples. A C-N complex is suggested as the source of the compensating defect level for the N-implanted samples. Sheet resistance data vs anneal temperature and estimates of the depth of the defect levels are reported. This result will have application to heterojunction bipolar transistors and complementary heterostructure field effect transistor technologies that employ C-doped AIGaAs or GaAs layers along with high temperature post-implant isolation processing.

Modeling of InGaAs optical constants and its application to spectroscopic ellipsometry study of strained InGaAs/AlGaAs based structures

There is a broad spectrum of electronic devices, e.g., high electron mobility, heterojunction bipolar (HBTs) and modulation doped field effect (MODFETs) transistors, and optoelectronic devices, e.g., low-threshold quantum-well (QW) lasers, which employ strained InyGa1-yAs layers to improve device performance due to the enhanced flexibility in the electronic structure. These devices have very promising applications. For example, the ultra-low threshold lasers are going to play a major role in computer interconnect circuits due to their low-power consumption. Strainlayer InGaAs/GaAs QW lasers are of considerable interest as a possible candidate for pumping the upper states of Er-doped silica fiber amplifiers of optical networks.

Thermally Stable Oxygen and Nitrogen Implant Isolation of C-Doped Al0.35Ga0.65As

ABSTRACTOxygen and nitrogen ion implantation have been applied, for the first time, to C-doped Al0.35Ga0.65As layers produce high resistivity regions (ps ≥ 1×1010 Ω/□) that are stable after annealing at 900 ºC. A dose threshold for stable compensation for both O and N ions was found above 8×1013 cm-2 for samples doped at 2×1018 cm-3. Although O implantation has been reported to form stable compensation in Si-doped and Be-doped AlGaAs, the ability of nitrogen implantation to produce thermally stable compensation has not been previously reported and may be due to a C-N complex. The existence of this C-N complex is supported by results for O- and N-implants into C-doped GaAs where N formed thermally stable compensation but O did not. Sheet resistance data versus anneal temperature and estimates of the depth of the defect levels are reported. This result will have application to heterojunction bipolar transistors and complementary heterostructure field effect transistor technologies that employ C-doped AlGaAs or GaAs layers along with high temperature post-isolation processing.

Monolithically integrated HBT/MESFET circuit

The first circuit demonstrated using monolithically integrated GaAlAs/GaAs heterojunction bipolar transistors (HBTs) and metal-semiconductor field effect transistors (MESFETs) is described. The fabrication technology is a natural extension to our baseline HBT technology. The planarity of the device fabrication process allows the MESFETs and HBTs to be closely spaced. The circuit, a CML-DCFL-CML convenor, is an important building block for the future integration of HBT and MESFET circuitry. This circuit consists of HBTs, and enhancement (E) and depletion (D) mode MESFETs. The circuit operated properly at 1 GHz.

Use of Low Temperature Si MBE Growth Techniques for High Performance SiGe/Si Electronics

ABSTRACTThrough the use of low temperature Si molecular beam epitaxy (MBE), we have fabricated high performance Si1−x Gex/Si heterojunction bipolar transistors (HBTs) and bipolar inversion-channel field effect transistors (BICFETs). Our growth method employs a high temperature Si-assisted desorption followed by MBE growth at a temperature only slightly in excess of the critical temperature for two-dimensional layer-by-layer growth. [1] At this temperature, segregation of Sb has previously been shown to be kinetically limited. [2] In addition, significantly more strain can be frozen into such an epitaxial layer as compared with those grown at higher temperatures.[3] Secondary ion mass spectroscopy (SIMS) data verify the abruptness of the Sb doping profiles in our device structures. High resolution x-ray diffraction (HRXRD) data are consistent with planar, coherently strained Si1−x Gex layers in our HBTs. A gain of 2690 (3210) is observed in our BICFETs at 300 K (7 K).

Gallium arsenide (device applications)

The device potential of GaAs and the problems inhibiting its widespread use are examined. Problems encountered in growing wafers are stringent process requirements for obtaining pure material, high susceptibility to lattice defects, small size (2-3 in) of wafers that can be grown, low thermal conductivity necessitating a special heat sink, and the uselessness of native oxide, which must be avoided during manufacture. With respect to the microelectronic properties, the speed of GaAs devices is much higher, with electron velocities measured up to five times that of comparable silicon devices. With very high transconductances and low input capacitances, GaAs devices can obtain much higher gain-bandwidth products (up to 15-20 GHz) that lead to switching speeds of up to 50 ps, about half the speed of silicon. However, this speed advantage erodes at high levels of integration, where costs demand simple and compact packaging. The reasons whey technologies available today for silicon devices-the bipolar junction transistors (BJTs) and field effect transistors (FETs), specifically the MOSFETs-do not work well for GaAs are examined, and new device technologies for GaAs devices-the metal-semiconductor field-effect transistor (MESFET) and the heterojunction bipolar transistor (HBT)-are described.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A new high-dynamic range dual-loop power-to-current amplifier

The design and performance of a balanced amplifier with a dual differential feedback loop in a high-frequency BiFET (bipolar-field effect transistor) process (f/sub T/=3 GHz) is presented. By means of this dual feedback loop, a linear, accurately known input impedance is obtained, combined with a high-output impedance. The noise figure of the realized amplifier is lower than 3 dB. The amplifier is especially intended for low-noise, low-distortion termination of antennas, cables, or filters and for driving bipolar switching mixers up to frequencies well above 100 MHz. >

Response to “numerical simulation of an AlGaAs/GaAs bipolar inversion channel field effect transistor”

Response to “numerical simulation of an AlGaAs/GaAs bipolar inversion channel field effect transistor”

Numerical simulation of an AlGaAs/GaAs bipolar inversion channel field effect transistor

The first two-dimensional numerical simulation of an AlGaAs/GaAs Bipolar Inversion Channel Field Effect Transistor (BICFET) has been carried out. The device simulated consists of a 30 Å wide n + layer sandwiched between a p + Al 0.35Ga 0.65As emitter and a p-GaAs collector region. Access to the n + inversion layer is provided through a source contact. The electrical characteristics of the device are obtained through solutions to the drift and diffusion equations and Poisson's equation. Space charge and potential distributions, and current flow paths in the device are computed to aid in the interpretation. In the bias range investigated, computed current densities are of the order of 10 5 A/cm 2 and current gains reach as high as 10 5. The general behavior of the device is found to be similar to that of an HBT.

Resonant tunneling through quantum wells: Physics and device applications

Recent results on the physics and device applications of resonant tunneling (RT) are discussed. RT through parabolic quantum wells has been observed for the first time; up to fourteen resonances have been detected in one structure. The first ten correspond to RT through the quasi-bound-states of the parabolic well while the other ones are ascribed to electron interference effects associated with virtual levels in the quasi-continuum energy range above the collector barrier. A new hot-electron spectroscopy technique based on RT has been applied to the study of hot minority-electron injection in GaAs via band discontinuities. These results are important for the design of RT transistors. RT bipolar transistors and RT field effect transistors are discussed in the last section of the paper.

GaAs Heterojunction Bipolar Transistor Device and IC Technology

ABSTRACTGaAs/AlGaAs N-p-n heterojunction bipolar transistor (GaAs HBT) device and integrated circuit technology which offers key advantages over advanced silicon bipolar and III-V compound field-effect transistors is maturing towards system insertion. The TRW device and IC fabrication process, basic HBT dc and RF performance, examples of device and IC applications, and technology qualification work are presented and serves as a basis for discussing overall technology issues and impact. A relaxed 3-μm emitter-up, self-aligned base ohmic metal (SABM) HBT process and simplified molecularbeam epitaxial profiles are used for near-term producibility. The HBTs have simultaneous fT, fmax≈20–40 GHz and dc current gain ß≈50–100 at collector current density JC=3 kA/cm2 and Early voltage VA≈200–300 with capability for MSI-LSI integration levels. Versatile dc-20 GHz analog, 3–6 Gb/s digital, and 2–3 Gs/s A/D conversion functions are demonstrated with a common 3-μm SABM HBT process which facilitates single-chip multifunctional capability. Key improvements are realized over Si bipolar and GaAs-related FET (e.g. MESFET and HEMT) approaches in operational frequency, gain-bandwidth product, harmonic distortion, 1/f noise, power consumption, and size reduction.

A technology concept for integrated detector electronics with CMOS compatible devices

There is a growing interest to use CMOS technology for analog circuits which are integrated with detectors. To fulfill various special demands, CMOS compatible devices are needed for reference elements, output drivers and low noise amplifier stages. In this paper integrated passive elements like resistors, capacitors and Zener diodes will be reviewed. Compatible bipolar and junction field effect transistors are presented.

A new ultra-high-speed heterojunction transistor

A new type of heterojunction bipolar transistor, designated the BICFET, (for Bipolar Inversion Channel Field Effect Transistor), is proposed. Unlike the conventional heterojunction bipolar transistor (HBT), the BICFET does not have a base. Instead, it relies on a field effect action to induce and modulate an inversion channel (which replaces the base) at the interface between the wide- and narrow- bandgap materials, to control current flow in the system.The BICFET has the high current gain associated with HBTs. However, since the BICFET does not have a base layer, it does not experience the deleterious base layer effects, such as charge storage, recombination, base transit time, etc. In particular, it has a much lower input capacitance and the capability of much higher current drive than a HBT, the combination of which augurs well for very high speed operation.In addition to the basic theory, common-emitter (CE) output and input characteristics are generated for two practical systems, and a possible integrated structure is indicated. A small-signal CE model for the device is also presented. The model predicts h cut-off frequencies as high as 10,000 GHz; however, in practice, collector transit time effects will reduce the cut-off frequency to about 600 GHz.

Subsurface junction field effect transistor

A novel bipolar compatible junction field effect transistor structure is described in this paper. The device is fabricated using a single boron implant at energies high enough to result in a p-type channel fully embedded in an n-epitaxial background material. The channel is buffered from the Si-SiO 2 interface by a thin n-type region which improves device reproducibility. The structure has been used to make subvolt pinchoff devices especially suitable for micropower low voltage operation.

Input Amplifiers for Optical PCM Receivers

This paper describes the noise performance of input amplifiers for optical pulse-code-modulation repeaters. The noise is treated in terms of an effective noise generator in parallel with the photocurrent induced in the detector and the effective noise, in turn, is related to error performance. The analysis applies to both conventional and integrating front ends. Both field effect and bipolar transistor amplifiers are treated. For the latter, an optimum bias current that minimizes the effect of thermal noise is derived. Finally, predicted and measured performance are compared for silicon field-effect transistor input amplifiers at 6.3 Mb/s and 50 Mb/s, and for bipolar transistor and GaAs field-effect transistor input amplifiers at 274 Mb/s.