Showing papers on "Breakdown voltage published in 1979"

High voltage thin layer devices (RESURF devices)

Abstract: The application of a somewhat unusual diode structure opens the possibility to make novel kinds of high voltage devices even with very thin epitaxial or implanted layers. In the new structures crucial changes in the electric field distribution take place at or at least near the surface. The acronym RESURF (REduced SURface Field) was chosen.

Analytical models of threshold voltage and breakdown voltage of short-channel MOSFET's derived from two-dimensional analysis

Abstract: Analytical models of threshold voltage and breakdown voltage of short-channel MOSFET's are derived from the combination of analytical consideration and two-dimensional numerical analysis. An approximate analytical solution for the surface potential is used to derive the threshold voltage, in contrast with the charge conservation approach which has been usually taken. It is shown that the surface potential depends exponentially on the distance from the drain, and this causes the threshold voltage to decrease exponentially with decreasing channel length. The analytical dependence of threshold voltage on device dimensions, doping, and operating conditions is verified by accurate two-dimensional calculations, and the accuracy of the model is attained by slight modification. The breakdown voltage of a short-channel n-MOSFET is lowered by a positive feedback effect of excess substrate current. From two-dimensional analysis of this mechanism, a simple expression of the breakdown voltage is derived. Using this model, the scaling down of MOSFET's is discussed. The simple models of threshold and breakdown voltage of short-channel MOSFET's are helpful both for circuit-oriented analysis and process diagnosis where statistical use of the model is often needed.

Optimum doping profile for minimum ohmic resistance and high-breakdown voltage

Abstract: The optimum doping profile of a lightly doped layer that introduces the minimum series resistance and sustains a given junction breakdown voltage is derived. The theory applies to a one-dimensional Schottky diode and qualitatively to the collector or drain doping profiles of transistors. The minimum series resistance is found to be about 3.7 × 10-9 V\min{B}\max{2.6} Ω.cm2for an n silicon layer. The optimum doping profile can be closely approximated by a conventional uniformly doped n-n+structure.

Characteristics and limitation of scaled-down MOSFET's due to two-dimensional field effect

Abstract: Practical limitations of minimum-size MOS-LSI devices are investigated through measurement of experimental devices. It is assumed that scaled-down MOSFET's are limited by three physical phenomena. These are 1) poor threshold control which is caused by drain electric field, 2) reduced drain breakdown voltage due to lateral bipolar effects, and 3) hot-electron injection into the gate oxide film which yields performance variations during device operation. Experimental models of these phenomena are proposed and the smallest possible MOSFET structure, for a given supply voltage, is considered. It is concluded that the smallest feasible device has a channel length of 0.52 µm and a gate oxide thickness of 9.4 nm when the supply voltage is 1.5 V. Reliable threshold control is most difficult to realize in an MOS-LSI with the smallest devices.

Deep-depletion breakdown voltage of silicon-dioxide/silicon MOS capacitors

Abstract: The deep-depletion breakdown voltage of silicon-dioxide/ silicon MOS capacitors is determined by the ionization-integral method, with potential distributions computed by two-dimensional relaxation techniques. Calculations cover the range of substrate doping between 1014and 1018cm-3and oxide thickness between 0.01 and 5.00 µm, providing plots of breakdown voltage versus substrate impurity concentration with oxide thickness as parameter. A universal and normalized criterion is derived for field uniformity in terms of the ratio of oxide thickness to the maximum (breakdown) width of the silicon depletion region: this ratio should be larger than 0.3 in order not to have field concentration around the edges of the metal plate.

Analytical models of threshold voltage and breakdown voltage of short-channel MOSFETs derived from two-dimensional analysis

Abstract: An approximate analytical solution for the surface potential is used to derive the threshold voltage. It is shown that the surface potential depends exponentially on the distance from the drain, and this causes the threshold voltage to decrease exponentially with decreasing channel length. The analytical dependence of threshold voltage on device dimensions, doping, and operating conditions is verified by accurate two-dimensional calculations, and the accuracy of the model is attained by slight modification. The breakdown voltage of a short-channel n-MOSFET is lowered by a positive feedback effect of excess substrate current. From two-dimensional analysis of this mechanism, a simple expression of the breakdown voltage is derived. Using this model, the scaling down of MOSFETs is discussed. The simple models of threshold and breakdown voltage of short-channel MOSFETs are helpful both for circuit-oriented analysis and process diagnosis where statistical use of the model is often needed.

Effect of Avalanche Space Charge Field on the Calculation of Corona Onset Voltage

Abstract: Many researchers have suggested that the space charge field of the primary electron avalanche should not be neglected in calculating the corona onset voltage based on the streamer criterion. Some researchers consider only the space charge field of the positive ions created during the avalanche growth, while others consider only the space charge field of the electrons at the head of the avalanche. The authors suggest that both space charge fields should be considered in calculating the corona onset voltage. Computer programs are written to calculate the breakdown voltage (for uniform field: parallel-plane geometry) and corona onset voltage (for non-uniform field: point-to-plane geometry). The space charge fields of both the positive ions and the electrons are considered in the calculations. Results are obtained for air and SF6 for a wide range of geometrical parameters and gas pressures. The results indicate that the effect of space charge fields is to reduce the corona onset voltage (or breakdown voltage in uniform field geometry) by less than 5%.

In0.53Ga0.47As p-i-n photodiodes for long-wavelength fibre-optic systems

Abstract: We describe p-i-n photodiodes fabricated from In0.53Ga0.47As grown lattice-matched on InP substrates. These diodes exhibit low junction capacitance (C<1 pF at 20 V reverse bias), low dark current (?10 nA), high break-down voltage (110 V) and wide photoresponse extending beyond 1.7 ?m.

Measurement of the effective ionisation coefficient and the static breakdown voltage in SF6 and nitrogen mixtures

Abstract: The effective ionisation coefficient alpha /p20 is measured for E/p20 from 70 to 160 V cm-1 Torr-1, and the static breakdown voltage Vs between parallel plates for p20d from 8 to 130 Torr cm, for SF6 and nitrogen mixtures. It is found that the alpha /p20 of the mixtures may be approximated by a linear function of the partial pressure of SF6 at fixed E/p20 and that Paschen's law holds for the p20d may be estimated with good accuracy from the Vs of the respective pure gases using an experimental formula of Takuma et al. (1972) which has been used for much larger p20d.

Plasma Buildup and Breakdown Delay in a Triggered Vacuum Gap

Abstract: The phenomena leading to the surface flashover across solid insulators in vacuum and the subsequent spread of the trigger plasma thus formed to bridge the main gap in a triggered vacuum switch are investigated experimentally. The results show that the breakdown proceeds in two stages. In the first stage a plasma is formed by electrons releasing and ionizing absorbed gases. The electrons are field emitted at the insulator-electrode junction and the breakdown delay is primarily affected by the trigger voltage. In the second stage the trigger plasma expands into the main gap with a speed depending on the trigger current and trigger electrode geometry, in accordance with a simple model.

Particle-Initiated Breakdown in SF6 Insulated Systems Under High Direct Voltage

Abstract: Conducting particle charging and detachment into a compressed SF6 coaxial electrode gap energized with high direct voltage have been investigated using the charge simulation technique and dimensional analysis.

Transient Behavior in Transformer Oils: Prebreakdown and Breakdown Phenomena

Abstract: A quantitative correlation between streamer velocities and impulse breakdown voltages has been established for point-plane geometries. We have extended these studies to less divergent fields (rod-plane) where we have identified two regions for impulse breakdown in liquids, oneiationinitiation-Inintrolled and a second controlled by streamer propagation rate. Which controls breakdown is determined by electrode geometry (field divergence), liquid composition, and wave shape. The influence of these parameters has been determined and a general model for the prediction of impulse breakdown voltage is proposed.

Electrical phenomena at the surface of electrically stressed metal cathodes. I. Electroluminescence and breakdown phenomena with medium gap spacings (2-8 mm)

Abstract: Spectral intensity measurements have been made of the light emitted from discrete points on the surface of electrically stressed metal cathodes. DC and pulsed breakdown voltage measurements have also been made immediately following surface arcing treatment. These show that the significant differences occur between different electrode materials. It is shown that the phenomena of electroluminescence, electron emission and vacuum breakdown, are all consistent with a model based on the production of conducting filamentary channels, electroformed through surface oxide or oxide type impurities by the action of the applied field.

Current‐voltage characteristics of ZnO‐Bi2O3 heterojunction

Abstract: Thin‐film junctions of ZnO‐Bi2O3 have been made by sputtering. The junction breakdown voltage ranges from 2.3 to 3.0 V when ZnO is positively biased. A negative resistance usually appears after the breakdown. When ZnO is negatively biased, the current is proportional to an exponential function of the applied voltage with a built‐in barrier of roughly 0.8 V. These characteristics and their temperature dependence on being cooled down to 77 °K will be discussed in terms of a qualitative n‐n heterojunction with interface states.

Relation between oxide thickness and the breakdown voltage of a planar junction with field relief electrode

Abstract: A semitheoretical relationship has been developed between the surface breakdown of a planar junction protected by an overlaying field plate and its description in terms of resistivity and oxide thickness. This has been confirmed experimentally on p+-n diodes in 45-Ω . cm material for a wide range of oxide thicknesses.

Static Field Breakdown of SF6-N2 Mixtures in Rod-Plane Gaps

Abstract: The static field breakdown and corona characteristics of SF6-N2 mixtures in non-uniform field gaps for applied voltages of positive and negative polarities are discussed Mixtures containing 0 to 100% SF6 are studied over a pressure range of 100 to 500 kPa The results show that for such gaps, the dielectric behavior of SF6-N2 mixtures is very similar to that of pure SF6 A discontinuity is reported in the breakdown voltagepressure characteristics of SF6 and SF6-N2 mixtureswhen the rod electrode is positive The pressure at which this discontinuity is observed is higher for the mixtures than for pure SF6 and is affected by the mixture ratio The breakdown voltage for certain mixtures is up to 70% higher than that of pure SF6 When the rod electrode is negative, breakdown strength of N2 is very sensitive to the presence of small amounts of SF6 and is almost doubled if 02% of SF6 is added to N2 The breakdown and corona characteristics are discussed in detail

Vertical MOSFET with reduced turn-on resistance

Abstract: A vertical MOSFET structure which includes a drain which comprises a high conductivity region and a low conductivity region. The high conductivity drain region is contoured so as to minimize the device turn-on resistance without degrading the device breakdown voltage.

Breakdown voltage resistor obtained through a double ion-implantation into a semiconductor substrate, and manufacturing process of the same

Abstract: An implanted resistor structure for semiconductor integrated circuit devices is formed by a double ion-implantation providing a high breakdown voltage resistor.

Dielectric breakdown of supercritical helium

Abstract: The paper reports the results of an experimental investigation into the dielectric-breakdown behaviour of super-critical helium, in the range from 42 to 30 K and 04 to 15 MPa under dc, ac and standard impulse voltages, to assist the development of superconducting power cables At helium densities above 80 kg m−3, the uniform-field breakdown voltage for dc or ac is about 55 MV m−1 at 08 MPa and has a slight pressure dependence In nonuniform fields, the breakdown voltage with a negative electrode is considerably increased by corona stabilisation in the density range from 30 to 83 kg m−3

Statistical Property of the Breakdown of Vacuum Circuit Breakers and its Influence on the Surge Generation in Capacitive and Reactive Current Interruption

Abstract: The statistical property of the breakdown of a contact in vacuum has been studied experimentally. The results are summarized so as to express the cumulative probability of breakdown as a function of the applied voltage and the spacing of the contact. The expression of the probability distribution is applied to analyze the switching surge generation by a vacuum circuit breaker in the load current interruption of capacitive and inductive circuits. It was shown that a completely restriking -free condition is quite difficult to realize particularly at high system voltages. The statistics of the switching surges due to the restrikings and the problems of circuit protection for them are given based on the analysis.

Open base bipolar transistor protective device

Abstract: A transistor, used in the switching of current in an inductive load, is protected by a similar transistor connected between collector and base The protective transistor has a lower breakdown voltage than the transistor being protected When the inductive load produces a voltage surge, the protective transistor breaks down first and turns the protected transistor on so that the surge is absorbed in an active transistor not in breakdown and therefore capable of dissipating the surge without damage Since the surge is arrested at high voltage the time required to complete the arrest is shortened

Reversible Electrical Breakdown of Lipid Bilayer Membranes

Abstract: Charge pulse experiments were performed with lipid bilayer membranes from oxidized cholesterol/n-decane at relatively high voltages (several hundred mV). The membranes show an irreversible mechanical rupture if the membrane is charged to voltages in the order of 300 mV. In the case of the mechanical rupture the Voltage across the membrane needs about 50 μs-200 μs to decay completely to zero. At much higher voltages, applied to the membrane by charge pulses of about 500 ns duration, a decrease of the specific resistance of the membranes by nine orders of magnitude is observed (from 108Ωcm2 to 0.1Ωcm2) without a mechanical rupture of the lipid bilayer membrane. Due to the high conductance increase (breakdown) of the bilayer it is not possible to charge the membrane to a larger value than the critical potential difference Vc. For 1 M alkali ion chlorides V c was about 1 V. The temperature dependence of the electrical breakdown voltage Vc is comparable to that being observed with cell membranes [1]. Vc decreases between 2°C and 48°C from 1.5 V to 0.6 V in the presence of 1 M KC1.

Impulse Breakdown and Corona Characteristics for Rod-Plane Gaps in Mixtures of SF6 and Nitrogen with Less Than 1% of SF6 Content

Abstract: Measurements of 50% impulse breakdown voltage were made mainly in SF6-N2 mixtures containing 0.1% SF6 content by pressure, over the range of 1-5 bar and gap lengths of 10 to 50mm. The gaps were tested under both negative and positive polarities with impulse voltages of 1.8/50 ?sec and 310/3500 ?sec. Data on the spatial growth of ionization was obtained in the form of still photographs of spark discharges and prebreakdown coronas. These results show that the positive impulse breakdown of nitrogen in the pressure region of 1-2.5 bar increases considerably with addition of small traces of SF6. The increase in the breakdown strength of mixtures with less than 1% SF6 is shown to be associated with a movement of the initiation point of the discharge, away from the tip of the rod electrode. This movement is referred to here as "creep effect" of the spark trajectories and its variation is examined with pressure, gap length and impulse front duration. On the basis of the results of this work and absorption characteristics of SF6, N2 and SF6-N2 mixtures, the anomalous behavior of SF6-N2 mixtures with SF6 content of the order of 0.1% is interpreted as the result of an anode shielding mechanism produced by a positive space charge, which is affected by factors such as polarity and waveform of the applied voltaae, gas pressure and mixture ratio.

Temperature dependent characteristics of a PIN avalanche photodiode (APD) in Ge, Si and GaAs

Abstract: A theoretical assessment is presented based on a modification of Baraff's theory in order to compare the temperature dependence of several characteristics, including breakdown voltage, excess noise factor, effective ionization rate ratio and efficiency in Ge, Si and GaAs PIN avalanche photodiodes. The temperature coefficient of avalanche breakdown voltage in a high field region is studied. Finally the response time of a PIN APD in these materials is discussed.

An Improved Method for Calculating the Impulse Strength of Wood Porcelain Insulation

Abstract: This paper describes an improved method of predicting the breakdown voltage and volt-time characteristic of wood-porcelain combinations. The model accounts for the different voltage waveshapes that stress each element of the combination. The integration method is used to evaluate the breakdown and the time to breakdown of each element, from which are derived the insulation strength and the volt-time characteristic of the combination. This method can reproduce laboratory results to within 10 percent for a wide range of wood-porcelain combinations.