Showing papers on "Schottky barrier published in 1984"
TL;DR: In this paper, the Schottky barrier heights for metal-semiconductor interfaces with a variety of metals have been calculated, and they are in excellent agreement with experiment for interfaces with various metals.
Abstract: Simple physical considerations of local charge neutrality suggest that near a metal-semiconductor interface, the Fermi level in the semiconductor is pinned near an effective gap center, which is simply related to the bulk semiconductor band structure. In this way “canonical” Schottky barrier heights are calculated for several semiconductors. These are in excellent agreement with experiment for interfaces with a variety of metals.
1,121 citations
TL;DR: In this paper, a simple criterion for zero-dipole band lineups is proposed, which gives excellent agreement with experimental band lineup, and the close connection between heterojunction band line up and Schottky barrier formation is emphasized.
Abstract: At any semiconductor heterojunction there is an interface dipole associated with quantum-mechanical tunneling, which depends on the band “lineup” between the two semiconductors. When the interface dipolar response dominates, the actual band discontinuity must be close to that unique value which would give a zero interface dipole. A simple criterion is proposed for this zero-dipole lineup, which gives excellent agreement with experimental band lineups. The close connection between heterojunction band lineups and Schottky barrier formation is emphasized.
669 citations
TL;DR: In this article, the Schottky-barrier heights of NiSi2layers grown under ultrahigh-vacuum conditions on n-type Si(111) are found to be 0.65 and 0.79 eV for type-A and type-Bepitaxial systems, respectively.
Abstract: Electrical behaviors at two single-crystal metal-semiconductor interfaces are studied. Schottky-barrier heights of NiSi2layers grown under ultrahigh-vacuum conditions on n- type Si(111) are found to be 0.65 and 0.79 eV for type-Aand type-Bepitaxial systems, respectively. These results are compared with the proposed theoretical models of Schottky barriers.
364 citations
TL;DR: In this article, a junction grid is incorporated beneath the Schottky barrier to pinch off current flow during reverse blocking, which reduces the forward voltage drop from 0.6 to 0.4 V without causing excessive reverse leakage currents.
Abstract: A new concept for reducing the forward voltage drop of Schottky rectifiers without incurring excessive reverse leakage currents is introduced. In this concept, a junction grid is incorporated beneath the Schottky barrier to pinch off current flow during reverse blocking. Experimental results that demonstrate the capability to reduce the forward drop from 0.6 to 0.4 V without incurring an increase in leakage current are presented.
129 citations
TL;DR: In this article, the Schottky barrier height φB of ideal (no interfacial oxide) contacts to GaAs have been measured for a diverse group of 14 metals by using currentvoltage and capacitance-voltage methods.
Abstract: The electrical properties, with emphasis on Schottky‐barrier height φB, of ideal (no interfacial oxide) contacts to GaAs have been measured for a diverse group of 14 metals by using current‐voltage and capacitance–voltage methods. The contact interfaces were formed under controlled ultrahigh vacuum conditions by metal evaporation onto clean (100) surfaces of both n‐type and p‐type GaAs. The range of φB for n‐type contacts is 0.96 to 0.62 eV in the decreasing order: Cu, Pd, Ag, Au, Al, Ti, Mn, Pb, Bi, Ni, Cr, Co, Fe, and Mg. For p‐type contacts, the φB range is 0.45 to 0.62 eV. No simple correlation is apparent between φB and contact metal work function nor between φB and the metal–GaAs interface chemistry.
113 citations
TL;DR: In this article, the Schottky barrier height φB of ideal (no interfacial oxide) contacts to GaAs has been measured for a diverse group of eleven metals, including Cu, Pd, Ag, Au, Al, Ti, Pb, Bi, Ni, Cr, and Fe.
Abstract: The Schottky‐barrier height φB of ideal (no interfacial oxide) contacts to GaAs has been measured for a diverse group of eleven metals, Cu, Pd, Ag, Au, Al, Ti, Pb, Bi, Ni, Cr, and Fe, by using current‐voltage and capacitance‐voltage techniques. The contacts were formed by metal evaporation in ultrahigh vacuum onto clean (100) surfaces of both n‐type and p‐type GaAs. For n‐type contacts φB ranged from 0.96 to 0.72 eV, in the metal order listed above; for p‐type contacts φB ranged from 0.45 to 0.62 eV. No simple correlation was found between φB and metal work function nor between φB and the chemical reactivity at the metal‐GaAs interface.
109 citations
TL;DR: In this paper, the electrical properties of Ti-pSi metaloxide-semiconductor diodes have been studied as a function of temperature and applied voltage, using conventional Schottky barrier capacitance-voltage (C•V) and current voltage measurements.
Abstract: The electrical characteristics of Ti‐pSi metal‐oxide‐semiconductor diodes have been studied as a function of temperature and of applied voltage, using conventional Schottky barrier capacitance‐voltage (C‐V) and current‐voltage (I‐V) measurements. The results show a strong deviation from those expected from thermionic emission and from the minority carrier injection theory for the current mechanism. Unlike other authors who proposed a multistep recombination‐tunneling mechanism, we have stressed that a model based on the inhomogeneity of the barrier height over the diode area predicts a temperature and voltage behavior of the I‐V characteristic similar to the recombination‐tunneling mechanism. The concept of inhomogeneity proposed by former authors is supported by Auger depth concentration profiles which show an intermixed region of Ti and Si. It is observed that the equilibrium semiconductor band bending exhibits a stronger temperature dependence than expected from the variation of the semiconductor Fermi level.
99 citations
TL;DR: Shallow (≲100 A) antimony ion implantation on n-type silicon is shown to reduce the effective barrier height on Al Schottky diodes formed on the implanted surface irrespective of postimplant annealing as discussed by the authors.
Abstract: Shallow (≲100 A) antimony ion implantation on n‐type silicon is shown to reduce the effective barrier height on Al Schottky diodes formed on the implanted surface irrespective of postimplant annealing. The mechanisms of barrier reduction are quite different in the two cases. In the postimplant annealed case, the antimony is activated resulting in barrier height reduction due to the surface N+ dopant charge, while in the unannealed case, lattice damage causes barrier height reduction as observed earlier for ion etched silicon surfaces.
74 citations
TL;DR: In this article, the Schottky barrier is located at the interface of polythiophene and the electrolytic medium, and no decrease in the photocurrent is observed after many hours of irradiation, confirming the high stability of these polymer.
70 citations
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05 Jun 1984TL;DR: In this paper, a V-grooved vertical FET is used to expose a nearly vertical surface that is Si implanted or regrown with graded n-type GaAs/GaAlAs before a gate contact is deposited on the vertical structure.
Abstract: High transconductance vertical FETs are produced in III-V epitaxially grown layers doped n, p and n, with the in-between submicron (0.15 μm) layer serving as the FET channel. The layer on the drain side of the channel may be thicker (3 μm) than on the source side (1.5 μm). The structure is V-grooved to expose a nearly vertical surface that is Si implanted or regrown with graded n-type GaAs/GaAlAs before a gate contact is deposited on the vertical structure. An alternative to employ a heterostructure with GaAlAs layers for the source and drain, and GaAs for the channel layer. Graded GaAs/GaAlAs is then selectively regrown in the channel layer.
62 citations
TL;DR: In this paper, the extent of As depletion during 1 keV to 5 keV argon sputtering of GaAs surfaces was measured using electron photoelectron spectroscopy (XPS).
Abstract: Auger and electron photoelectron spectroscopy were used to measure the extent of As depletion during 1 keV to 5 keV argon sputtering of GaAs surfaces. This depletion was correlated with a general decrease in the barrier height of the rectifying Au contact deposited in situ. However, nondestructive angle resolved XPS measurements showed As was depleted at the outer surface more by 1 keV than 3 keV argon. These effects are explained based on a combined work effective work function model and creation of a donor like surface damage layer. The donor layer was correlated with As depletion by sputtering. Deep level trap formation and annealing of sputtering effects were studied.
TL;DR: In this article, Schottky barrier heights for epitaxial NiSi2 and CoSi2 layers grown under ultrahigh vacuum conditions on Si(111) were determined for single crystal silicide-silicon interfaces.
Abstract: Capacitance–voltage and current–voltage characteristics at single crystal silicide–silicon interfaces are studied. Schottky barrier heights are determined for epitaxial NiSi2 and CoSi2 layers grown under ultrahigh vacuum conditions on Si(111). These results demonstrate that there is an influence of interface structure on Schottky barrier height. This dependence suggests a reassessment of many previous interpretations or models of Schottky barriers. It also shows that experimentally measured barrier heights of metal–semiconductor systems with inhomogeneous interface structure are likely to be the averages from those associated with different regions of the interface. Homogeneous metal–semiconductor interfaces are therefore the simplest and most desirable systems for the study of Schottky barrier mechanisms. In particular, the present epitaxial silicide–silicon interfaces represent ideal candidates for detailed theoretical investigations based on experimentally obtained atomic structures.
TL;DR: In this paper, an orgainic p-n junction photovoltaic cell with a thin film of TPyP exhibited stronger spectral sensitization and better spectral match to a solar spectrum than the Schottky barrier cells using either 3-pyridyl porphyrin (TPyP) and ZnPc.
Abstract: Electric and photovoltaic characteristics of an orgainic p‐n junction photovoltaic cell are described, where the p‐type and n‐type compounds used are phthalocyaninatozinc (II) (ZnPc) and 5, 10, 15, 20 ‐tetra (3‐pyridyl) porphyrin (TPyP), respectively. The p‐n junction cell with a thin film of TPyP exhibited stronger spectral sensitization and better spectral match to a solar spectrum than the Schottky barrier cells using either TPyP and ZnPc. The energy conversion efficiency found was about 2% for monochromatic light at 430 nm.
01 Jan 1984
TL;DR: The Schottky barrier model for metal-semiconductor diodes was first proposed by Braun as mentioned in this paper in 1874, who reported the rectifying nature of metallic contacts on copper, iron, and lead sulfide crystals.
Abstract: A rectifying metal-semiconductor contact is known as a Schottky barrier after W. Schottky, who first proposed a model for barrier formation. Our knowledge of metal-semiconductor diodes is more than a century old. F. Braun,(1) in 1874, reported the rectifying nature of metallic contacts on copper, iron, and lead sulfide crystals. Although numerous experimental and theoretical studies have been carried out since then, our understanding of the metalsemiconductor junctions is still far from complete. This is perhaps due to the fact that their performance is highly process dependent.
TL;DR: In this article, WN/GaAs contacts show good Schottky diode characteristics even after high temperature annealing, and both the ideality factor n and flat band barrier height B0C of contacts showed nearly constant values of about 1.1 and 1.15 eV, respectively, for annaling at about 800°C and for anannealing longer than 20 min.
Abstract: WN film formation by a reactive rf sputtering and WN/GaAs Schottky contact characteristics were investigated with the intent of forming a gate for self-aligned MESFETs. WN/GaAs contacts show good Schottky diode characteristics even after high temperature annealing. Both the ideality factor n and flat band barrier height B0C of contacts showed nearly constant values of about 1.1 and 1.15 eV, respectively, for annealing at about 800°C and for annealing longer than 20 min.
TL;DR: In this paper, a cryogenic 3-mm receiver was developed which fully utilizes the lownoise potential of Schottky diodes by approaching the shot-noise limit within 10 percent.
Abstract: A cryogenic 3-mm receiver has been developed which fully utilizes the low-noise potential of Schottky diodes by approaching the shot-noise limit within 10 percent. With a broad-band mixer design which properly terminates the input sidebands and reactively terminates the second harmonic of the local oscillator and its sidebands, the double sideband (DSB) mixer noise temperature is 35 K in the best case. This design has given an average DSB receiver noise temperature of 75 K over the 80 to 115-GHz band with a best noise temperature of 62 K.
TL;DR: In this paper, the surface symmetry was determined by reflection high energy electron diffraction (RHEED) and the position of the valence band maximum relative to the Fermi level was measured using angle resolved UV photoelectron spectroscopy (ARUPS) at normal emission.
Abstract: The band bending on GaAs(001) surfaces prepared by molecular beam epitaxy (MBE) have been studied for n‐ and p‐type materials. Surfaces with c(4×4), c(2×8), and (4×6) reconstruction ranging from As to Ga rich have been investigated. The surface symmetry was determined by reflection high energy electron diffraction (RHEED) and the position of the valence band maximum relative to the Fermi level was measured using angle resolved UV photoelectron spectroscopy (ARUPS) at normal emission. The position of the Fermi level relative to the valence band maximum was found to be ∼0.7 eV for n‐type and ∼0.5 eV for p‐type material, with a slightly increasing trend in going from Ga‐ to As‐rich surfaces. For the (4×6) reconstructed n‐type samples the growth termination method was found to have a significant influence on the band bending. The results obtained here are in very good agreement with previous measurements of the Al–GaAs(001) Schottky barrier height indicating that the electronic properties of this junction are...
TL;DR: In this paper, the electrical characteristics of Schottky diodes fabricated on silicon surfaces subject to low-energy (10 keV) argon ion implantation have been studied as a function of Ar+ ion dose.
Abstract: The electrical characteristics of Schottky diodes fabricated on silicon surfaces subject to low‐energy (10 keV) argon ion implantation have been studied as a function of Ar+ ion dose. Significant changes in electrical characteristics are seen for ion doses as low as 5×1011 cm−2, well below the amorphization threshold dose for Si. In conjunction with the ion energy threshold established earlier for Si surface damage effects (∼25 eV), these results outline fundamental limits on the effect of ion‐assisted dry etching processes on Si surface barriers.
TL;DR: In this article, the effects of various spatial distributions of pinning sites (e.g., surface defects, clusters of anions and/or adsorbed metal atoms) and variations of their energy levels upon surface potentials and their depth distribution via a two-dimensional finite difference program that integrates Poisson's equation were studied.
Abstract: Various models of Schottky barrier formation have been proposed in the last few years which involve metallurgical interactions at the metal–semiconductor interface. Most of these models involve nonuniform lateral variations in the surface potential. For metallic clusters and/or anion clusters, these variations involve a relatively large size scale (tens to hundreds of angstroms). For interface defect formation, the suggestion of cluster formation energy as the driving force for defect formation could also lead to a nonuniform distribution of pinning sites on a similar size scale. We have studied the effects of various spatial distributions of pinning sites (e.g., surface defects, clusters of anions and/or adsorbed metal atoms) and variations of their energy levels upon surface potentials and their depth distribution via a two‐dimensional finite difference program that integrates Poisson’s equation. Our results suggest that surface sensitive spectroscopies provide a less than exact measure of pinning level...
TL;DR: In this paper, the electrical properties of these interphases control the charge transport through the junction, and generally symmetric, non-ohmic characteristics are found. But no evidence of Schottky barrier formation is found.
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01 Mar 1984
TL;DR: In this paper, a multilayer structure formed by laminating an a-Si film, a high-melting point metal film and an aluminum film was proposed to suppress the operation of the P channel without modifying significantly the manufacturing process.
Abstract: PURPOSE:To enable to suppress the operation of the P channel without modifying significantly the manufacturing process by a method wherein the respective structure of the source and drain electrodes of an FET is made into a multilayer structure formed by laminating an a-Si film, a high-melting point metal film and an aluminum film in an order of the a-Si film, the high-melting point metal film and the aluminum film. CONSTITUTION:A high-melting point metal 12 of a thin film is formed on the substrate, whereon a patterning of an a-Si film 4 has been finished, using a vacuum evaporating apparatus of a sputtering device, and successively, a source electrode 6 and a drain electrode 7, both made of Al and so forth, are coated on the high-melting point metal 12 by a vacuum evaporating method, a supptering method and so forth. After a resist for the patterns of the source and drain electrodes 6 and 7 was left in the photo process, an etching is performed on the source and drain electrodes 6 and 7, and successively, an etching is performed on the high-melting point metal 12 and an FET is formed. So long as the high-melting point metal 12 is a metal to form a Schottky barrier when the metal has come into contact with the a-Si film 4, that will do. Particularly, it is desirable that metals of more than one, which are chosen from a metal group of Cr, Ta, W, Ni, Mo and Pt, are used for the manufacture of the high-melting point metal 12. It is desirable that the film thickness of the high-melting point metal 12 is made into a thickness of 1-100Angstrom .
TL;DR: In this paper, the authors investigated the near surface damage introduced during fabrication of Schottky barrier diodes by electron-beam (E•beam) deposition of various metals on n-type silicon using deep level transient spectroscopy.
Abstract: Near‐surface damage introduced during fabrication of Schottky barrier diodes (SBDs) by electron‐beam (E‐beam) deposition of various metals on n‐type silicon has been investigated using deep level transient spectroscopy. The main defect was observed at Ec −0.42 eV and is annealed out at 400 °C. The interaction of E‐beam deposition induced defects with defects which had been introduced in the substrate by irradiation with high‐energy electrons was also observed in Pd and Pd/Au SBDs. Therefore erroneous conclusions can be made when using SBDs fabricated by E‐beam deposition to characterize defects introduced by some other process near the interface of a SBD.
TL;DR: In this article, high speed GaAs Schottky barrier photodiodes have been fabricated and characterized and the response of the detectors to light modulated at 1-18 GHz has been directly measured.
Abstract: High‐Speed GaAs Schottky barrier photodiodes have been fabricated and characterized. These detectors have 3‐dB bandwidths of 20 GHz and quantum efficiencies as high as 70%. The response of the detectors to light modulated at 1–18 GHz has been directly measured. Microwave modulated optical signals were obtained by using a LiNbO3 traveling wave modulator and by heterodyning two laser diodes.
TL;DR: In this paper, the first example of a recombination enhanced defect reaction in InP was reported and the defect exhibits a reduction in activation energy of recovery from 1.3 eV under pure thermal annealing to 0.42 eV with minority-carrier injection.
Abstract: The first example of a recombination enhanced defect reaction in InP is reported. The major defect E(0.79 eV) introduced by 1‐MeV electron irradiation of p+n junctions, formed by Zn‐doped epilayers on undoped n‐type substrates, is not observed with Schottky barrier structures on similar material. The defect exhibits a reduction in activation energy of recovery from 1.3 eV under pure thermal annealing to 0.42 eV with minority‐carrier (hole) injection. The enhanced reaction rate is proportional to the square of the injected current showing that the process results from two particle capture.
IBM1
TL;DR: In this paper, the Schottky barrier height of sputtered TiN on both p - and n -type silicon was determined by I-V and C-V measurements and the experimental results were explained in terms of sputtering damage.
Abstract: The Schottky barrier height of sputtered TiN on both p - and n -type silicon was determined by I-V and C-V measurements. The barrier height is found to increase on n -Si and to decrease on p -Si, upon thermal annealing. The experimental results are explained in terms of sputtering damage. This damage is modeled by donor-like traps whose concentration decays exponentially from the silicon surface. A characteristic length equal to 45 A accounts for the observed characteristics. The trap-free values of the barrier height were obtained by I-V measurements after sequential thermal annealing up to 600°C. These values are φ Bn = 0.55 V on n -type and φ Bp = 0.57 V on p -type silicon.
Patent•
04 Jun 1984TL;DR: In this paper, a guard-ring-equipped Schottky barrier diode, which can have shortened reverse recovery time and increased withstand voltage, has been proposed, where an insulative film (23) with an opening over part of the guard ring (25) is formed over the region between the edge of the barrier layer (27) and the guard circle (25).
Abstract: A guard-ring-equipped Schottky barrier diode, which can have shortened reverse recovery time and increased withstand voltage, has a Schottky barrier layer (27) formed on a semiconductor substrate (20) of a first conductivity type and a guard ring (25), which has a second conductivity type, formed on surface of the substrate (20) isolated from but surrounding the periphery of the barrier layer (27). An insulative film (23) with an opening over part of the guard ring (25) is formed over the region between the edge of the Schottky barrier layer (27) and the guard ring (25). A high-resistance layer (26) is formed on this opening and is connected with the Schottky barrier layer (27) by a metal electrode (28). The size of the area between the guard ring (25) and the end ofthe barrier layer (27) is less than the sum of the widths of the depletion layers of the guard ring (25) and the barrier layer (27) at the time when the lower voltage of either the barrier layer (27) breakdown voltage or the guard ring (25) breakdown voltage is applied.
TL;DR: The double Schottky barrier is often formed at the grain boundary in polycrystalline semiconductors and the barrier height is shown to fluctuate in value due to the random nature of the impurity positions as discussed by the authors.
Abstract: A double Schottky barrier is often formed at the grain boundary in polycrystalline semiconductors. The barrier height is shown to fluctuate in value due to the random nature of the impurity positions. The magnitude of the fluctuations is 0.1 eV, and the fluctuations cause the barrier height measured by capacitance to differ from the one measured by electrical conductivity.
TL;DR: Theoretical predictions of electronic energy levels associated with s− and p−bonded substitutional point defects at (110) surfaces of InAs and other III-V semiconductors are presented and discussed in this article.
Abstract: Theoretical predictions of electronic energy levels associated with s‐ and p‐bonded substitutional point defects at (110) surfaces of InAs and other III–V semiconductors are presented and discussed. The specific defects considered for InAs are: anion and cation vacancies, the (native) antisite defects InAs and AsIn, and 26 impurities. The predicted surface‐defect deep levels are used to interpret Schottky barrier height data for (a) n‐ and p‐(InAs) and (b) the alloys AlxGa1−xAs, GaAs1−xPx, In1−xGaxP, and In1−xGaxAs. The rather complicated dependence of the Schottky barrier height φB on alloy composition x provides a nontrivial test of the theory (and competing theories). The following unified microscopic picture emerges from these and previous calculations: (1) For most III–V and group IV semiconductors, Fermi‐level pinning by native defects can explain the observed Schottky barrier heights. (2) For GaAs, InP, and other III–V semiconductors interfaced with nonreactive metals, the Fermi‐level pinning is no...
TL;DR: In this article, the characteristics of phase-coupled laser arrays fabricated using Schottky barriers on the p-contact to confine the current flow to 5 or 10 stripes on 9 μm centers are described.
Abstract: The characteristics of phase-coupled laser arrays fabricated using Schottky barriers on the p-contact to confine the current flow to 5 or 10 stripes on 9 μm centers are described. The gain guided laser spots are very equally spaced, and in some cases do not coincide exactly with the position or number of conducting stripes. The self adjusting nature of the active region, together with the phase shift of π between the neighboring N laser spots results in extremely smooth far-field patterns consisting of 2 narrow, intense outer lobes, and N-2 much weaker interior lobes. The mode structure closely approximates the higher order modes observed in wide stripe laser. The separation and width of the outer lobes is defined by diffraction theory, and determined by the separation and number of lasing spots. Deviations from diffraction theory are found in some cases. The contributions to the far field were studied by examining the magnified image of the exit facet as a narrow slit was passed across the far field. The phase contributions present in the far field were studied by introducing a relative phase shift between the two symmetric halves of the far field. The relative phase change modifies the interference pattern of the magnified near-field image, causing a spatial shift of the imaged spots in the plane of the junction.