The metal-nitride-oxide-silicon (MNOS) transistor—Characteristics and applications
01 Aug 1970-Vol. 58, Iss: 8, pp 1207-1219
TL;DR: In this article, the authors present a unified approach to the characterization of both stable and variable turn-on voltage MNOS transistors, based on an extensive investigation of charge transport and storage in MNOS structures.
Abstract: Recent advances in silicon nitride deposition techniques have led to the emergence of the metal-nitride-oxide-silicon (MNOS) integrated circuit technology as an alternative and supplement to the existing MOS technology. Applications of MNOS field-effect transistors have been proposed for both logic circuits (as an alternative to MOS transistors) and nonvolatile memory arrays This paper reviews the characteristics and applications of MNOS transistors. It presents a unified approach to the characterization of both stable and variable turn-on voltage MNOS transistors. The analysis is based on an extensive investigation of charge transport and storage in MNOS structures. The different modes of transistor operation are described and analyzed in terms of the physical parameters of the two-layer dielectric structure. Understanding of the physical mechanisms underlying transistor operation is applied to the optimization of transistor structure and performance for different digital integrated circuit applications. The feasibility of these applications is demonstrated by fabrication of a nonvolatile semiconductor storage array and a nonvolatile flip-flop.
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TL;DR: In this article, a series of experiments designed to characterize the charging effect of thermal SiO2 films with water was conducted. And they found that if water is diffused into a SiO 2 film, water related centers are formed which act like electron traps with capture cross section of approximately 1.5 × 10−17 cm2.
Abstract: When electron currents flow in thermal SiO2 films which have been exposed to water, a buildup of negative charge occurs in the oxide. This paper describes a series of experiments designed to characterize this charging effect. It is found that if water is diffused into a SiO2 film, water related centers are formed which act like electron traps with capture cross section of approximately 1.5 × 10−17 cm2. Experiments are described which show that when one of these centers captures an electron, atomic hydrogen is released which diffuses away and escapes or reacts and a stable negative charge is left behind. Electrochemical charging effects of this type have not previously been considered, although they may play a very important role in some semiconductor device failure effects.
400 citations
TL;DR: In this paper, an analytical theory for the switching time constant of thin oxide MNOS structures is derived and curves of the switching-time constant versus the nitride field are computed, which are useful in the design of MNOS-memory transistors.
Abstract: The properties of thin oxide MNOS structures are studied. An analytical theory for the switching time constant is derived and curves of the switching time constant versus the nitride field are computed. These curves are useful in the design of MNOS-memory transistors. The theory is compared with experiments. The normal current in the thin oxide MNOS structures is assumed to be a modified Fowler-Nordheim current. At small oxide thicknesses and low nitride field, an additional current is shown to exist that is attributed to direct tunneling into traps in the nitride. The discharge of MNOS structures is briefly discussed and is shown to be due to a direct tunneling of charge carriers from traps in the nitride into the semiconductor.
136 citations
TL;DR: In this article, a two-band Si3N4 impurity conduction model with silicon microcrystals is examined, the latter serving as Poole-Frenkel centres in the nitride volume as well as trapping and recombination centers in the regions close to the electrodes.
Abstract: A method is proposed for determining the electron and hole components of stationary current flowing through an MIS structure and the hole and electron components of the stationary current in an MNOS structure have been determined. It is shown that the experimental results may be explained by a two-band Si3N4 conduction model. A two-band Si3N4 impurity conduction model with silicon microcrystals is examined, the latter serving as Poole-Frenkel centres in the nitride volume as well as trapping and recombination centres in the regions close to the electrodes.
[Russian Text Ignored].
97 citations
IBM1
TL;DR: In this paper, a survey and assessment of nonvolatile semiconductor memory devices including charge-storage devices and FET's with ferroelectric gate insulators is made, and novel structures which provide nonvolatility as well as the theoretical limit of memory array density are also explored.
Abstract: An attempt is made to survey and assess the nonvolatile semiconductor memory devices including charge-storage devices and FET's with ferroelectric gate insulators. The charge-storage devices are further divided into two groups: 1) charges-trapping devices such as the MNOS and the MAOS, and 2) floating-gate devices such as the FAMOS and the DDC. Approaches for achieving virtual nonvolatility in otherwise volatile semiconductor memories are briefly disscused. Novel structures which provide nonvolatility as well as the theoretical limit of memory array density are also explored.
89 citations
TL;DR: In this paper, a program that quickly determines the energy band diagrams based on a simple analytical model was created to explore the behavior of various oxide stacks with the ability to easily vary important parameters like oxide material, electron affinity, bandgap, dielectric constant, and thickness.
Abstract: Energy band diagrams for MOS devices are essential for understanding device performance and reliability. Introduction of high-k gate stacks with a silicon dioxide (SiO2) interfacial layer requires an even greater understanding of the energy band behavior. A program that quickly determines the band diagrams based on a simple analytical model was created. It is used to explore the behavior of various oxide stacks with the ability to easily vary important parameters like oxide material, electron affinity, bandgap, dielectric constant, and thickness. The usefulness of this program to predict potential reliability issues is also demonstrated
87 citations
Cites background from "The metal-nitride-oxide-silicon (MN..."
...This is particularly true with dual dielectric stacks studied for high-dielectric-constant materials such as hafnium oxide (HfO2)/SiO2 [9], silicon nitride (Si3N4)/SiO2 [10], and aluminum oxide (Al2O3)/SiO2 [1]....
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References
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Book•
01 Jan 1967
TL;DR: The Planar Technology of Semiconductor Surfaces is described in this article, where it is shown that the planar planar technology can be used to model the surface effects on p-n junction transistors.
Abstract: The Planar Technology. Solid-State Technology. Vapor-Phase Growth. Thermal Oxidation. Solid-State Diffusion. Semiconductors and Semiconductor Devices. Elements of Semiconductor Physics. Semiconductors under Non-Equilibrium Conditions. p-n Junction. Junction Transistor. Junction Field-Effect Transistors. Surface Effects and Surface-Controlled Devices. Theory of Semiconductor Surfaces. Surface Effects on p-n Junctions. Surface Field-Effect Transistors. Properties of the Silicon-Silicon Dioxide System.
2,394 citations
TL;DR: In this article, the relative effective mass in the forbidden energy gap was found to be about 0.4, which is lower by a factor of five to ten than the expected values, probably due to trapping effects.
Abstract: Electronic conduction in thermally grown SiO2 has been shown to be limited by Fowler‐Nordheim emission, i.e., tunneling of electrons from the vicinity of the electrode Fermi level through the forbidden energy gap into the conduction band of the oxide. Fowler‐Nordheim characteristics have been observed over more than five decades of current for emission from Si, Al, and Mg. If previously measured values of the barrier heights are used, the slopes of the Fowler‐Nordheim characteristics (log J/E2 vs 1/E) imply values of the relative effective mass in the forbidden band of about 0.4. These values take into account corrections for image‐force barrier lowering and for temperature effects. The absolute values of the currents are lower by a factor of five to ten than the theoretically expected values, probably due to trapping effects. The temperature dependence of the current was found to follow the theoretical curve from 80°–420°K. However, an inconsistent relative effective mass of about 0.95 had to be assumed....
1,640 citations
TL;DR: In this paper, it was shown that at any given temperature and electric field, the current transport is essentially independent of the substrate material, the film thickness, or the polarity of the electrodes.
Abstract: Measurements of current‐voltage characteristics have been performed on Au‐Si3N4‐Mo and Au‐Si3N4‐Si (degenerate substrate) structures of various nitride‐film thicknesses from 300 A to 3000 A and over a range of temperatures. The films are deposited by the process of reaction of SiCl4 with NH3. It is found that at any given temperature and electric field, the current transport is essentially independent of the substrate material, the film thickness, or the polarity of the electrodes.It is proposed that the current‐transport mechanisms are bulk controlled rather than electrode controlled. The conduction‐current density, J, is the sum of three contributions: J = J1+J2+J3, where J1∼E exp {−q[φ1 − (qE/πe0ed)½]/ kT}, J2∼E2 exp (−E2/E), and J3∼E exp (−qφ3/kT). At high fields and high temperatures J1 dominates the current conduction (the Poole‐Frenkel effect or internal Schottky effect); one obtains a barrier height of (1.3±0.2) V for φ1 and a value of 5.5±1 for the dynamic dielectric constant ed. At high fields a...
445 citations
TL;DR: In this article, the theory of the MOS transistor in the gradual channel approximation is presented with the assumption of constant surface and bulk charge, and constant surface mobility, from the simple theory, the complete design equations are derived and design curves are calculated.
Abstract: The theory of the MOS transistor in the gradual channel approximation is presented with the assumption of constant surface and bulk charge, and constant surface mobility. From the simple theory, the complete design equations are derived and design curves are calculated. From the analysis, the equivalent circuit parameters of the device are related to the basic properties of the material and geometry of the device. The simple theory is then critically compared with experimental measurements of MOS transistors with circular geometry. The comparison shows good general agreement with the theory of the dc characteristics but discrepancies are found for the differential characteristics such as the transconductance and the gate capacitance. The possible sources of the discrepancies are discussed.
260 citations
TL;DR: In this article, a simple physical model that predicts charge accumulation at the dielectric interface of metal-nitride-oxide-silicon (MNOS) structures is proposed and verified experimentally.
Abstract: A simple physical model that predicts charge accumulation at the dielectric interface of metal‐nitride‐oxide‐silicon (MNOS) structures is proposed and verified experimentally. The model is based on the presence of steady‐state current flow in the dielectric structure. Interface‐charge accumulation is shown to be determined by the requirement for continuity of current through the structure under steady‐state conditions. Continuity of current is established by accumulation of either positive or negative charge for a given polarity of charging voltage, depending on the relative current‐field characteristics of the silicon nitride and silicon dioxide layers. Due to the exponential nature of the current‐field characteristics, the time required to reach steady state is a strong function of the applied charging voltage. This leads to the observed charge storage property of MNOS devices. The hysteresis characteristic observed in MNOS structures is shown to be time‐dependent with a tendency to merge into a single‐...
196 citations