Semiconductor Device Technology Research Articles

Semiconductor materials for present-day solid-state electronics

This review paper outlines advances and challenges in semiconductor materials research and the lines along which the techniques for growing large-diameter crystals and large-area epitaxial heterostructures are progressing. We discuss potential applications of quantum-size heterostructures and thin-film structures based on hydrided amorphous semiconductors. The major problems facing the technology of semiconductor materials and devices are outlined

Nanotechnology and Model Catalysis: The Use of Photolithography for Creating Active Surfaces

New and very stable model catalysts have been developed. Two types of samples on oxidized 4-inch wafers were produced using processes that are generally employed in semiconductor device technology. A single wafer exhibits 109 to 1010 active sites on an otherwise flat silicon oxide surface. Sputter etching of a number of bilayers (Pd/SiO2), stacked on an oxidized Si wafer surface resulted in billions of isolated towers, consisting of disks of active metal layers, separated by inert substrate material. A second system was produced by etching pits into a heavily oxidized 4-inch Si wafer. Active material was deposited into the pits by e-beam evaporation or spin-coating of precursor solutions. The topography and chemical composition, and the changes induced by the reaction conditions applied, including stability and chemical behavior of the nanostructured systems, were investigated by means of AFM, SEM, temperature-programmed methods and XPS.

Ion implantation damage model for B, BF2, As, P, and Si in silicon

In this article we describe a newly proposed and consistent damage model in Monte Carlo simulation for the accurate prediction of a three-dimensional as-implanted impurity profile and point defect profile induced by ion implantation in (100) crystal silicon. An empirical electronic energy loss model for B, BF2, As, P, and Si self-implants over a wide energy range has been proposed for silicon-based semiconductor device technology and development. Our model shows very good agreement with secondary ion mass spectrometry data over a wide energy range. For damage accumulation, we have considered the self-annealing effects by introducing our proposed nonlinear recombination probability function of each point defect for computational efficiency. For the damage profiles, we compared the published Rutherford backscattering spectrometry (RBS)/channeling data with our results of phosphorus implants. Our damage model shows very reasonable agreements with the RBS/channeling experiments for phosphorus implants.

Optoelectronic Properties and Applications of Rare-Earth-Doped GaN

As discussed in the accompanying articles in this issue ofMRS Bulletin, the optical properties of rare-earth (RE) elements have led to many important photonic applications, including solid-state lasers, components for telecommunications (optical-fiber amplifiers, fiber lasers), optical storage devices, and displays. In most of these applications, the host materials for the RE elements are various forms of oxide and nonoxide glasses. The emission can occur at visible or infrared (IR) wavelengths, depending on the electronic transitions of the selected RE element and the excitation mechanism. Until recently, the study of semiconductors doped with RE elements such as Pr and Er has concentrated primarily on the lowest excited state as an optically active transition. The presence of transitions at IR wavelengths (1.3 and 1.54 μm) that are coincident with minima in the optical dispersion and the loss of silica-based glass fibers utilized in telecommunications, combined with the prospect of integration with semiconductor device technology, has sparked considerable interest.The status and prospects of obtaining stimulated emission in Si:Er are reviewed by Gregorkiewicz and Langer in this issue and by Coffa et al. in a previousMRS Bulletinissue. While great progress is being made in enhancing the emission intensity of Er-doped Si, it still experiences significant loss in luminescence efficiency at room temperature, as compared with low temperatures. This thermal quenching was shown by Favennec et al. to de crease with the bandgap energy of the semiconductor. Hence wide-bandgap semiconductors (WBGSs) are attractive candidates for investigation as hosts for RE doping.

Dopant impurity diffusion from polymer diffusants and its applications in semiconductor device technology. A review

Dopant impurity diffusion from polymer diffusants and its applications in semiconductor device technology. A review

Global executive: Intel's Andrew Grove on competitiveness

Executive Overview Andrew S. Grove has made outstanding contributions to both the business and academic communities. He co-founded Intel Corporation in 1968, and as the current chairman of the board and former CEO, led it to become the world's largest microprocessor manufacturer. With 1998 revenues surpassing $26 billion. Intel is also one of the world's most highly successful companies. Dr. Grove's spectacular achievements have been recognized by many organizations. Three prestigious awards he received in 1997 were Time magazine's Man of the Year, CEO magazine's CEO of the Year, and Industry Week magazine's Technology Leader of the Year. Dr. Grove has also been actively involved in the academic community, and has teaching appointments at the University of California, Berkeley, and the Stanford University Graduate School of Business. He holds several patents on semiconductor devices and technology, and has written over 40 technical papers and several books, including Physics and Technology of Semiconductor Devices (Wiley, 1967), High Output Management (Random House, 1983), One-on-One With Andy Grove (Putnam's Sons, 1987). and Only the Paranoid Survive (Doubleday, 1996). He has also been a frequent contributor to Fortune, The Wall Street Journal, The New York Times, and Working Woman magazine. Dr. Grove emigrated to the U.S. from Hungary and subsequently earned a BA in chemical engineering from the City College of New York, and a PhD from the University of California, Berkeley. Andrew Grove was a keynote speaker at the 1998 Academy of Management annual meeting. He used the opportunity to draw the attention of Academy members to an emerging phenomenon that he calls strategic inflection points. Dr. Grove discussed the fundamental changes that might alter the way business is conducted, and shared his opinions about the best adjustment practices available to remain competitive. An adapted version of his speech appears below, followed by an interview by the editor of The Executive.

Organic molecular beam deposition: technology and applications in electronics and photonics Invited Lecture

Organic semiconductors have been intensively studied over the past decades. The potential of this new class of materials for photonic and electronic device applications is demonstrated by successful fabrication of organic and organic-on-inorganic heterostructures for electroluminescent devices, photodetectors, and microwave diodes. The fabrication technology of organic semiconductor devices for both electronic and photonic applications is discussed. In contrast to spin-on or dipping techniques for fabrication of polymeric films, organic compounds with low molecular weight are sublimated under ultra high vacuum (UHV) conditions. The organic molecular beam deposition (OMBD) technology employed allows the reproducible growth of complex layer sequences with a defined thickness of various organic semiconductors in combination with dielectric films, different metallizations, and indium–tin oxide layers. Growth rates from 1–5 nm min-1 and substrate temperatures from 77 to 350 K are used. Organic-on-inorganic heterostructure diodes based on crystalline thin PTCDA (3,4,9,10-perylenetetracarboxylic dianhydride) films on III–V semiconductors are investigated with regard to microwave applications with reduced forward voltage and high cut-off frequencies in the GHz regime. Secondly, efficient organic light emitting diodes with bright emission in the blue [1-AZM-Hex (N,N′-disalicylidene-1,6-hexanediaminate)zinc(II)], green, [Alq3 (tris(8-hydroxyquinoline)-aluminum)], and red (Eu complexes) spectral region and with low operation voltages are presented. In general an onset voltage of 2.7 V, efficiencies up to 7 lm W-1 and a luminance up to 2×105 cd m-2 (CW, RT) are attained for N,N′-diphenyl-quinacridone doped Alq3 devices. An undoped device can be operated up to 5000 h without any loss in brightness and just a small increase of the driving voltage of about 2 V. Embedding emissive organic thin films with a narrow spectral characteristic into planar Fabry–Perot microcavities, a light intensity enhancement and a spatial redistribution of the emission is achieved.

Atomic transport in Cu/Ge and Co/Ge systems during ion-beam mixing

This paper reports on the atomic transport occurring across the interface of Cu/Ge and Co/Ge layers leading to the synthesis of Cu 3Ge and Co 2Ge phases under MeV Kr and Ar ion irradiations. These phases have potential applications in modern semiconductor device technology. The marker experiments show that in the case of Cu/Ge systems both Cu and Ge are mobile but Cu is the dominant moving species. On the other hand, in the case of the Co/Ge system only Ge atoms are mobile. The atomic movements during ion irradiation in these two systems have been explained on the basis of distribution of defect density and effects of thermodynamic forces.

The progress and impact of semiconductor device and processing technology innovation in Japan

This paper is an overview of the progress of the semiconductor devices and processing technologies innovated in Japanese industry and/or academia for the past 50 years and their impact on the advancement of electronics and the fulfillment of technical and social needs. This paper gives an overview of (1) a government initiative research project, (2) strategic research efforts in industry, (3) academia-government-industry collaboration, and (4) recent topics of semiconductor device and technology innovation.

MOS and bipolar gated thyristor: a thyristor with IGBT switching characteristics

The IGBT has become the device of choice in many high-voltage-power electronic applications, by virtue of combining the ease of MOS gate control with an acceptable forward voltage drop. However, designers have retained an interest in MOS gated thyristor structures which have a turn-off capability. These offer low on-state losses as a result of their latching behaviour. Recently, there have been various proposals for dual-gate devices that have a thyristor on-state with IGBT-like switching. Many of these dual gated structures rely on advanced MOS technology, with inherent manufacturing difficulties. The MOS and bipolar gated thyristor offers all the advantages of dual gated performance, while employing standard IGBT processing techniques. The paper describes the MBGT in detail, and presents experimental and simulation results for devices based on realistic commercial processes. It is shown that the MBGT represents a viable power semiconductor device technology, suitable for a diverse range of applications.

Prospects for terahertz technology

Addresses the prospects for terahertz technology in the context of satisfying the requirements for future communication systems and considers circuits and devices suitable for operation in this frequency regime. It examines the state-of-the-art in semiconductor device technology for terahertz applications and the prospects for monolithic integrated circuit technology at frequencies above 100 GHz. The author mentions the application to wireless LANs in particular.

Quantum functional devices for advanced electronics

Recent research in semiconductor device technology seems to be focused on reducing the cost and power dissipation of traditional Si CMOS integrated circuits, rather than developing new and advanced semiconductor devices. We believe however, that devices enter the nanometer-scale regime in the next century, where quantum mechanical effects play an important role in the device's function; therefore, it is important to continue basic research into the physics and technology of nanometer scale structures and device applications in order to cultivate “nanoelectronics”. This paper reviews our research activities on quantum functional devices and discusses our future research direction.

Trends in power semiconductor devices

This paper reviews recent trends in power semiconductor device technology that are leading to improvements in power losses for power electronic systems. In the case of low voltage ( 100 V) power rectifiers, the silicon P-i-N rectifier continues to dominate but significant improvements are expected by the introduction of the silicon MPS rectifier followed by the GaAs and SiC based Schottky rectifiers. Equally important developments are occurring in power switch technology. The silicon bipolar power transistor has been displaced by silicon power MOSFETs in low voltage ( 100 V) systems. The process technology for these MOS-gated devices has shifted from V-MOS in the early 1970s to DMOS in the 1980s, with more recent introduction of the UMOS technology in the 1990s. For the very high power systems, the thyristor and GTO continue to dominate, but significant effort is underway to develop MOS-gated thyristors (MCTs, ESTs, DG-BRTs) to replace them before the turn of the century. Beyond that time frame, it is projected that silicon carbide based switches will begin to displace these silicon devices.

Surface Passivation of Gaas-Based Phemt by Hydrogen Ion Irradiation

AbstractSurface passivation is a key issue in compound semiconductor device technology. The high density of surface states on unpassivated surfaces can lead to excessive non-radiative recombination at the surface, affecting optical devices, or provide leakage and low-field breakdown in electronic devices. Our previous studies on low energy, low-dose hydrogen ion treatment carried out at room temperature showed long-term improvement in the optical properties of near surface quantum wells. We have accordingly applied this process to GaAs-based pseudomorphic HEMTs (PHEMT) in order to improve their power performance. Although our process is designed so that the hydrogen reactions are confined to the surface of the substrate, a critical factor in the success of this treatment is the extent of in-diffusion of the hydrogen, and the possibility of dopant passivation. PHEMT structures were hydrogenated at various conditions and both Hall mobility and carrier density were monitored. For a low hydrogen ion dose (3 × 1016 cm−2) at 80 eV energy, some degradation of Hall mobility and carrier density was noted after the treatment, but full recovery of both parameters was achieved after a 400°C thermal anneal. Much higher hydrogen doses resulted in severe degradation of mobility and carrier density, which were only partially recovered after thermal anneal. Measurements on actual PHEMT devices showed an approximately 15% decrease in the transconductance, and in addition, a 60% decrease in the gate-to-drain leakage current after irradiation with 80 eV hydrogen ions at a dose of 3 × 1016 cm−2. The decrease of the leakage current indicates that passivation is taking place. The decrease of the transconductance suggests that hydrogen may be diffusing into the regions of the dopants. Optimization of the hydrogenation parameters should allow leakage reduction without sacrifice of transconductance.

13th International courses on semiconductor materials processing and device technology

13th International courses on semiconductor materials processing and device technology

Silicon-on-insulator technology for high temperature metal oxide semiconductor devices and circuits

The high temperature characteristics of devices and circuits realized in complementary metal oxide semiconductor (CMOS) technology on silicon-on-insulator (SOI) substrates are compared with other materials, and it is demonstrated that CMOS on SOI is presently the most suitable process for the realization of electronic circuits operating at up to more than 300 °C.

Investigation of Aluminum Thin Films Using Electron Backscatter Diffraction and the New Technique of Orientation Imaging Microscopy

AbstractAluminum thin films deposited onto silicon substrates coated with silicon dioxide or a layered structure of titanium and titanium nitride have been investigated using the combined techniques of electron backscatter diffraction and orientation imaging microscopy. By these methods the local texture and spatial distribution of texture components was established. It was observed that whereas the material exhibited an overall <111> texture with the in-plane direction <110> uniformly distributed, there were variations in the local texture and distribution of orientations with clustering of grains of similar orientation. Individual grains within the clusters were nearly perfect and varied in orientation by only a few degrees. The effective grain size differed greatly on whether the cluster size of similarly oriented grains or the diameter of individual grains within the cluster was considered to constitute the grain structure. No strong bias was found in favor of coincident site oriented grain pairs though in some cases the frequency of occurrence of low angle boundaries was less than is expected on a purely random basis. Additional experiments were carried out in order to establish the suitability of orientation imaging microscopy for microstructure characterization of interconnect lines in integrated semiconductor device technology.

Large-band-gap SiC, III-V nitride, and II-VI ZnSe-based semiconductor device technologies

In the past several years, research in each of the wide-band-gap semiconductors, SiC, GaN, and ZnSe, has led to major advances which now make them viable for device applications. The merits of each contender for high-temperature electronics and short-wavelength optical applications are compared. The outstanding thermal and chemical stability of SiC and GaN should enable them to operate at high temperatures and in hostile environments, and also make them attractive for high-power operation. The present advanced stage of development of SiC substrates and metal-oxide-semiconductor technology makes SiC the leading contender for high-temperature and high-power applications if ohmic contacts and interface-state densities can be further improved. GaN, despite fundamentally superior electronic properties and better ohmic contact resistances, must overcome the lack of an ideal substrate material and a relatively advanced SiC infrastructure in order to compete in electronics applications. Prototype transistors have been fabricated from both SiC and GaN, and the microwave characteristics and high-temperature performance of SiC transistors have been studied. For optical emitters and detectors, ZnSe, SiC, and GaN all have demonstrated operation in the green, blue, or ultraviolet (UV) spectra. Blue SiC light-emitting diodes (LEDs) have been on the market for several years, joined recently by UV and blue GaN-based LEDs. These products should find wide use in full color display and other technologies. Promising prototype UV photodetectors have been fabricated from both SiC and GaN. In laser development, ZnSe leads the way with more sophisticated designs having further improved performance being rapidly demonstrated. If the low damage threshold of ZnSe continues to limit practical laser applications, GaN appears poised to become the semiconductor of choice for short-wavelength lasers in optical memory and other applications. For further development of these materials to be realized, doping densities (especially p type) and ohmic contact technologies have to be improved. Economies of scale need to be realized through the development of larger SiC substrates. Improved substrate materials, ideally GaN itself, need to be aggressively pursued to further develop the GaN-based material system and enable the fabrication of lasers. ZnSe material quality is already outstanding and now researchers must focus their attention on addressing the short lifetimes of ZnSe-based lasers to determine whether the material is sufficiently durable for practical laser applications. The problems related to these three wide-band-gap semiconductor systems have moved away from materials science toward the device arena, where their technological development can rapidly be brought to maturity.

Pulsed laser quenching of metastable phases

The heat flux from an approximately 100 nm thick liquid layer produced by pulsed laser melting of a solid surface can be varied in the range 10 5–10 7 W cm −2, producing in turn cooling rates and solidification velocities in the range 10 9–10 11 K s −1 and 10 −1–10 1 m s −1 respectively. In this paper it is described how the heat flux can be changed experimentally and two examples are given of phase switching by control of the solidification velocity or the cooling rate. The choosen examples are amorphous silicon quenching which is, historically, the first transition to a metastable phase from an undercooled melt achieved by the pulsed laser technique, and the peculiar case of a titanium disilicide, of interest in semiconductor device technology, shown here to reveal quite different kinetics of solidification.

Application of the ERD method for hydrogen determination in silicon (oxy) nitride thin films prepared by ECR plasma deposition

Elastic recoil detection method was applied for the study of hydrogen in silicon nitride as well as silicon oxynitride thin films. For this purpose 2.4 MeV 4He+ ions produced by the Van de Graaff accelerator of JINR have been used. The thin films have been prepared by the electron cyclotron resonance plasma deposition technique. The physical properties of these layers, which play an important role in the technology of semiconductor devices, are strongly dependent on the amount of hydrogen incorporated during their deposition. The technique of the hydrogen depth determination by ERD is very important for the optimization of process parameters of the ECR plasma deposition of the silicon (oxy)nitride layers with optimal physical and electrical properties.