Showing papers on "Field effect published in 1981"
Patent•
22 Jul 1981TL;DR: In this paper, a light modulator consisting of a light-reflective metallized membrane defining a deformable mirror disposed over a semiconductor substrate of one conductivity type in which a matrix array of field effect transistors are formed, the metallised membrane cooperating with a matrix of floating metallic field plate members disposed on an insulating layer covering the substrate to define an array of air gap capacitors for line addressing by the field effect address transistors.
Abstract: A light modulator comprising a light-reflective metallized membrane defining a deformable mirror disposed over a semiconductor substrate of one conductivity type in which a matrix array of field effect address transistors are formed, the metallized membrane cooperating with a matrix of floating metallic field plate members disposed on an insulating layer covering the substrate to define an array of air gap capacitors for line addressing by the field effect address transistors. The floating metallic field plates are opaque to light and prevent photocharge generation in the active regions of the matrix array of field effect address transistors. The metallized membrane is spaced from the field effect address transistors and the metallic floating field plates by an upstanding semiconductor grid structure which is formed on the insulating layer of the semiconductor substrate and defines gate electrodes for the address transistors. The metallized membrane is mounted on the upstanding semiconductor grid structure by molecular bonding to the contact members disposed over the semiconductor grid structure. The metallized membrane is formed of a polymer of nitrocellulose as a flexible carrier layer on at least one surface of which is disposed a thin metallic coating providing a light reflective surface. Each transistor in the array of field effect address transistors is line-addressable, and the metallized membrane in each cell of the matrix array of air gap capacitors is deflectable inwardly toward the substrate in response to the signal on the address transistor corresponding thereto. Should a potential above a predetermined magnitude be placed on an individual air gap capacitor, the metallized membrane will transfer charge to the floating field plate and return to zero deflection. The floating field plate thereby not only acts as a light-blocking layer, but also prevents voltage-induced collapse of the metallized membrane to the surface of the semiconductor substrate.
565 citations
TL;DR: In this paper, electric field enhancement of emission from three non-Coulombic traps has been calculated: the shielded Coulombic potential, the polarization potential, and the dipole potential.
Abstract: Electric field enhancement of emission from three non‐Coulombic traps has been calculated: the shielded Coulombic potential, the polarization potential, and the dipole potential. Both the Poole‐Frenkel effect and phonon‐assisted tunneling have been included, and both were found to be important. The field effect can be used to distinguish between these potentials on the basis of their long range character. This effect is most important in interpreting the results of capacitance transient studies of deep levels.
204 citations
TL;DR: In this article, a method for calculating the relationship between the density of localized states in an amorphous semiconductor and the experimentally measured field-effect conductance is presented.
Abstract: A method for calculating the relationship between the density of localized states in an amorphous semiconductor and the experimentally measured field-effect conductance is presented. Commonly used simplifying assumptions of a constant space-charge density, zero-temperature statistics and a parabolic band-bending potential profile are removed and the errors that are introduced by using these approximations calculated. The method is used to show that the existence of a reported peak in the density of states at 0·4 eV below the conduction-band mobility edge of amorphous silicon (the Ex peak) cannot be proved through field-effect-conductance measurements.
64 citations
TL;DR: In this article, an enhancement mode high electron mobility transistors (E-HEMTs) with selectively doped GaAs/n-AlxGa1-xAs heterojunction structures grown by molecular beam epitaxy are described.
Abstract: Enhancement-mode high electron mobility transistors (E-HEMTs) with selectively doped GaAs/n-AlxGa1-xAs heterojunction structures grown by molecular beam epitaxy are described. E-HEMTs with 2- µm long gates have exhibited the square-law drain characteristic. The device has a gm of 409 mSmm-1 of gate width at 77 K and 193 mSmm-1 at 300 K. This value of gm at 77 K is the highest in all field effect devices reported thus far.
63 citations
TL;DR: In this paper, the electrical conductivity of discontinuous metal films in weak fields is investigated using a special chamber in a transmission electron microscope with a device for electron interference, and the results obtained allow us to evaluate critically the current theories and to show the important role of the charge effect in the conductivity.
37 citations
TL;DR: In this paper, the effects of magnetic field on the Anderson localization in two dimensions were investigated by extending the self-consistent treatment by Vollhardt and Wolfle to systems without time reversal symmetry.
Abstract: Effects of magnetic field on the Anderson localization in two dimension have been investigated by extending the self-consistent treatment by Vollhardt and Wolfle to systems without time reversal symmetry. The magnetic field is found to enhance the conductivity, though the static conductivity at absolute zero of temperature vanishes always within the present formulation which treats the field effect quasiclassically.
24 citations
TL;DR: In this article, the applied field acting synchronously upon a natural oscillating electric dipole associated with cell division is explained in terms of spin drag, which is observed to be linked to cell colony age.
16 citations
TL;DR: In this paper, the authors measured Id-Vd and C-V results on MOS capacitors which were fabricated on laser annealed polycrystalline silicon and used a scanned CW Ar+ laser to anneal the samples.
Abstract: Measured Id-Vd results on MOSFET's and C–V results on MOS capacitors which were fabricated on laser annealed polycrystalline silicon are presented A scanned CW Ar+ laser was used to anneal the samples Laser power varied from 10 to 15 W in increments of 1 W; beam diameter was about 40 μ m and scan rate was about 125 cm/s The field effect mobility, determined from Id-Vd measurements, increases with increasing laser power The effects of electron trapping in the polycrystalline silicon substrate were used to explain the observed mobility of the MOSFET's In transistors annealed at low power (
16 citations
TL;DR: In this paper, the density of gap states from the charge density measured in field-effect experiments is considered in terms of a model which incorporates electron correlation effects, and the minimum density is found to be ∼ 10 15 − 10 16 cm −3 eV −1.
13 citations
Patent•
20 May 1981
TL;DR: In this article, the memory cell uses GaAs MESFET depletion mode devices, with a pair of cross coupled active transistors, a load transistors and access transistors.
Abstract: The memory cell uses GaAs MESFET depletion mode devices, with a pair of cross coupled active transistors, a pair of load transistors, and a pair of access transistors. The level shifting required for Schottky Barriers is provided by capacitors in the cross coupling. A pair of initiation transistors are connected between the load and active transistors.
12 citations
Patent•
08 May 1981
TL;DR: An integrated circuit device for writing and reading information comprising an array of plural nonvolatile memory elements of insulated-gate field effect type formed on a semiconductor substrate of one conductivity type, which transistors constitute a control circuit for the memory elements, and a latch-up suppressant, comprising a long and narrow semiconductor region of the oneconductivity type which has an impurity concentration higher than that of the substrate, is formed between the array and the control circuit in a surface region of a substrate, with a predetermined voltage applied directly to the semiconductor regions.
Abstract: An integrated circuit device for writing and reading information comprising an array of plural non-volatile memory elements of insulated-gate field effect type formed on a semiconductor substrate of one conductivity type; plural sets of two complementary insulated-gate type field effect transistors of P-channel type and N-channel type formed on the substrate, which transistors constitute a control circuit for the memory elements; and a latch-up suppressant, comprising a long and narrow semiconductor region of the one conductivity type which has an impurity concentration higher than that of the substrate and is formed between the array and the control circuit in a surface region of the substrate, with a predetermined voltage applied directly to the semiconductor region.
Patent•
14 Aug 1981TL;DR: In this paper, the authors describe a monolithic static memory cell with two cross-coupled inverters, each comprised of a series connection of a field effect switching transistor and a load element designed as a FET.
Abstract: A monolithic static memory cell has two cross-coupled inverters each comprised of a series connection of a field effect switching transistor and a load element designed as a field effect transistor. The field effect transistors forming the load elements have their channel resistances of different values. A gate insulating layer of one of the load element field effect transistors has its charge state altered, preferably by electron beam writing, so that a change in a threshold voltage of the one transistor results in a change of its channel resistance relative to the channel resistance of the other load element transistor if it was under before the selective altering, or vice-versa.
TL;DR: In this paper, the effect of low energy noble gas ion bombardment on the electrical and optical properties of Si(211) surfaces has been investigated by surface conductivity and field effect measurements, ellipsometry and AES.
TL;DR: In this article, a new method for determining the screening length, static permittivity, and work function from field effect measurements in low-conductivity materials such as amorphous semiconductors is described.
Abstract: A new method for determining the screening length, static permittivity, and work function from field‐effect measurements in low‐conductivity materials such as amorphous semiconductors is described. The method is based on the charge‐flow transistor (CFT), a device structure which resembles a conventional metal‐oxide‐semiconductor field‐effect transistor (MOSFET), but with a portion of the gate metal replaced by the material under study. The interpretation of conventional field‐effect measurements is complicated by the simultaneous need to know both the mobility and the distribution of charges in the material. The CFT method complements conventional field‐effect measurements by providing independent information on the distribution of charges. This paper outlines the theory behind the new method, and presents the first experimental results that illustrate in part its use. The material used in these first experiments is a multicomponent chalcognide glass, Te39As36Ge7Si17P1.
TL;DR: In this paper, a field effect spectroscopy (FES) technique was developed to probe semiconductor insulator interface states optically. But it is not suitable for the case of thin-film transistor interfaces.
Abstract: We have developed a new technique termed field effect spectroscopy (FES) to probe semiconductor‐insulator interface states optically. It consists of photoconductivity measurements of the semiconductor channel between source and drain of a gated thin‐film transistor. By varying the gate voltage and thereby the potential at the insulator‐semiconductor interface, one can vary the relative contributions of bulk and interface states to the resistivity of the semiconductor channel. FES results for a variety of Al2O3:CdSe and SiO2:CdSe interface reveal a strong dependence of interface state density on fabrication conditions.
TL;DR: In this article, the density of localized gap states N(E) is calculated using a new scheme, which computes the charge density ρ (V) without explicit solution of Poisson's equation directly from the experimental field effect data avoiding fitting procedures and loops.
Abstract: The density of localized gap states N(E) is calculated using a new scheme, which computes the charge density ρ (V) without explicit solution of Poisson's equation directly from the experimental field effect data avoiding fitting procedures and loops. - In a second step N(E) is computed from ρ (V) considering finite temperature statistics. This method is applied to measurements on undoped glow discharge deposited a-Si:H films. It is found that high temperature annealing as well as strong illumination raise the density of states near midgap by about one order of magnitude.
TL;DR: In this paper, the dependence of changes in the electrical conductivity of continuous thin metallic films on the external electric field perpendicular to the film was calculated, and the Boltzmann transport equation was solved using Lucas boundary conditions.
TL;DR: In this paper, the ion dose dependence and the annealing behavior of GaAs after implantation with 200 keV 2 × 1012 −2 × 1016 Si+ ions/cm2 were studied by using optical absorption, reflection, photoluminescence, sheet-resistivity, Hall effect and field effect methods.
Abstract: Measurements have been made of the thermal conductivity and the electrical resistivity of the singlet-ground-state compounds of praseodymium, PrCu 6 and PrIn 3 , at temperatures between 1.5 and 15 K. The results on PrCu 6 clearly showed the effect of crystal-field splitting of the 4f level of Pr ion. By comparing the measured thermal conductivity with theory, information of the crystal-field level scheme is obtained. In PrIn 3 the effect is negligibly small below 15 K in agreement with known level scheme.
TL;DR: In this article, the Richardson-Schottky theory is used to show that the conformational PVF2 properties in the crystalline or in the non-crystalline regions control the space charge distribution.
Abstract: By means of modified field-effect measurements the properties of space charge distribution in polymers at the polymer-metal interface have been investigated. In general, these properties are due to excess charge and/or dipole orientation. The superposition of both effects is investigated in PVF2 (phase-II) in order to show whether the conformational PVF2 properties in the crystalline or in the noncrystalline regions control the space charge distribution. In the temperature region 60 °C
TL;DR: In this paper, the effect of pulsed electric fields on the magnetophonon structure in the transverse magnetoresistance of n-InSb and n-GaAs at 77 K has been investigated using a magnetic field modulation technique.
Abstract: The effect of pulsed electric fields on the magnetophonon structure in the transverse magnetoresistance of n-InSb and n-GaAs at 77 K has been investigated using a magnetic field modulation technique. The damping factor which represents an exponential decay of the oscillation has been deduced for the first time as a function of the total electric field, sum of the applied and Hall field. The damping factor increases with increasing the electric field beyond the threshold value, 100 V/cm for n-InSb and 500 V/cm for n-GaAs. The increase was found to be well explained in terms of the intra-collisional field effect proposed by Barker. The shift of the extremum positions at high electric field was reexamined experimentally and compared with the existing models. Non-parabolicity of the conduction band explains the shift in n-InSb but fails in n-GaAs.
TL;DR: In this paper, the localized state density in chemically vapour deposited amorphous silicon over a wide energy range was measured for the first time as 10 18 ∼ 10 20 cm −3 eV −1 in the range ± 0.4∼±0.5 eV around the Fermi level.
Abstract: New techniques to determined the localized-state density in chemically vapour deposited amorphous silicon over a wide energy range by the field-effect method are presented. The density is measured for the first time as 10 18 ∼ 10 20 cm −3 eV −1 in the range ±0.4∼±0.5 eV around the Fermi level. From the results it is suggested that the silicon atom network of CVD a-Si has a similar randomness to that of glow discharge a-Si, providing a density of tail states of about 10 19 ∼ 10 20 cm −3 eV −1 and native defect states of about 10 18 cm −3 eV −1 .
TL;DR: In this paper, the magnetostatic field dependence of the threshold current density in a GaAs/AlyGA1yAs double-heterostructure laser is investigated with the aid of the solution of the electron diffusion equation.
Abstract: The magnetostatic field dependence of the threshold current density in a GaAs/AlyGA1‐yAs double‐heterostructure laser is investigated with the aid of the solution of the electron diffusion equation. The reduction of the threshold current density by increasing the magnetic field strength can be significant when the difference in the energy band gap of the active and inactive layers at the heterojunction is small.
TL;DR: In this article, conductivity and Hall mobility were measured for CdSe films in normal and gated field effect structures and it was shown that potential barriers at grain boundaries play only a minor role in the conductivity.
TL;DR: Theoretical electrostatic characteristics of structures based on metals, insulators, and semiconductor layers with thickness comparable to or less than the Debye screening radius (critical thickness layers) and semiconductors of semi-infinite geometry are studied in this paper.
Abstract: Theoretical electrostatic characteristics of structures based on metals, insulators, and semiconductor layers with thickness comparable to or less than the Debye screening radius (critical thickness layers) and semiconductors of semi-infinite geometry are studied. Some peculiarities of electric field screening in semiconducting critical-thickness layers are revealed on the basis of computer calculations of potential and charge distributions as well as differential capacitances as a function of applied voltage. The obtained characteristics are compared with characteristics of analogous semiconducting structures with semi-infinite geometry.
[Russian Text Ignored]
Patent•
24 Jun 1981
TL;DR: In this article, the authors proposed to enhance the efficiency of a field effect semiconductor device by forming a reverse conductivity region to an active layer of predetermined depth in the section under the anode electrode of the active layer formed with cathode and anode thereon.
Abstract: PURPOSE:To enhance the efficiency of a field effect semiconductor device by forming a reverse conductivity region to an active layer of predetermined depth in the section under the anode electrode of the active layer formed with cathode and anode thereon. CONSTITUTION:An Si-doped GaAs active layer 14 is formed on a Cr-doped GaAs high resistance substrate 1, as a mesa structure with etching. Be ions are implanted to the section to be formed with anode electrode 19, and a P type region 16 reaching the substrate 11 is formed. Even if the region 16 does not reach the substrate 11, it may be preferred that there is the substrate 11 in the hole expansion length in the layer 14. Cathode electrode 18 and anode electrode 19 are formed through the contact layers 20, 21 respectively, and a planar type gunn diode is formed in this manner.