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Nuclear Science, IEEE Transactions on

Issue 6  Part 1 • Date Dec 1990

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Displaying Results 1 - 25 of 78
  • The effects of ionizing radiation on the breakdown voltage of p-channel power MOSFETs

    Publication Year: 1990 , Page(s): 2076 - 2082
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (512 KB)  

    The effects of ionizing radiation on the breakdown voltage of p-channel power MOSFETs were examined through two-dimension simulation. The breakdown-voltage performance of p-channel power MOSFETs was found to be very different from that of corresponding n-channel power MOSFETs. In p-channel devices, simulation showed breakdown-voltage enhancement for low values of positive oxide-trapped charge, Not, whereas for high values of Not , the breakdown voltage may or may not continue to increase, and may actually decrease in some topologies. For comparison, in n-channel devices, increases in Not always cause breakdown-voltage degradation. The uncertainties stem from the interaction of the depletion region of the device (which is a function of its termination method) with its isolation technology, making it difficult to predict breakdown voltage for large Not. However, insights gained through analysis of depletion-region spreading in p-channel devices suggest a termination/isolation scheme, the VLD-FRR, that will enhance p-channel device reliability in radiation environments View full abstract»

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  • Radiations hardening of a high voltage IC technology (BCDMOS)

    Publication Year: 1990 , Page(s): 2083 - 2088
    Cited by:  Papers (4)
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    A program was undertaken to radiation harden AT&T's existing power integrated circuit technology (BCDMOS). The BCDMOS technology is described. The radiation hardening approach is outlined. The modifications made to standard technology in an effort to harden the CMOS, DMOS, and NPN devices to four radiation environments (total dose, dose rate, single event upset (SEU), and neutrons) are discussed. Steps taken improve the performance of these devices to meet the circuit requirements are described. The tradeoffs involving the different devices and the different radiation environments are discussed. Initial results indicate a substantial improvement in hardness over existing commercial technology View full abstract»

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  • Simulation of design dependent failure exposure levels for CMOS ICs

    Publication Year: 1990 , Page(s): 2097 - 2103
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (488 KB)  

    The effects of design and bias on the radiation tolerance of ICs are studied, and an automated design tool is described that produces different designs for a logic function and presents important parameters of each design to a circuit designer for tradeoff analysis. It was shown by simulation and experimentally verified that the logic implementation of a circuit and the bias applied during irradiation are significant in determining the radiation tolerance of ICs. The software package aids designers in designing radiation-hard integrated circuits View full abstract»

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  • Radiation hardened SOS MOSFET technology for infrared focal plane readouts

    Publication Year: 1990 , Page(s): 2020 - 2025
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (380 KB)  

    A silicon-on-sapphire (SOS) MOSFET technology with a body contact technique is shown to provide a reduced kink effect and no edge leakage for a 500 krad(Si) Co-60 dose at 80 K. The approach utilizes a conventional local oxidation of silicon (LOCOS) field implant process with a silicon conducting layer remaining beneath the field oxide. For the design, with the body connection beneath the field oxide, the contact can be made at significant distances from the device and potentially only one contract is required for each well with a number of transistors in a well. Additional advantages of the approach are greater packing densities, body connection to both sides of the channel and compatibility with standard bulk CMOS field oxide processes View full abstract»

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  • Automated photocurrent and bussing extraction for dose-rate rail span collapse simulations

    Publication Year: 1990 , Page(s): 2104 - 2109
    Cited by:  Papers (1)
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    A simulator capable of simulating rail span collapse from layout-level inputs was developed. The simulations require radiation-induced photocurrent partitioning among proximal physical collection regions and electrical contacts to the power distribution network. The simulation approach incorporates simple geometric rules for current division inside a contiguous region along with the automated extraction of the power distribution network. Experimental results to verify the current division algorithms are also presented. Pixel-plane and scan-line techniques used for the automated extraction of the power distribution network are described. For simulation of the circuit, a simulator using conjugate-gradient algorithms is used. A postsimulation processor maps the actual supply rails onto the layout itself for easy identification of critical subcircuits View full abstract»

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  • The effect of ionizing radiation on sol-gel ferroelectric PZT capacitors

    Publication Year: 1990 , Page(s): 1713 - 1717
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (288 KB)  

    Ferroelectric (FE) thin-film capacitors are irradiated to 100 Mrad(Si) with 10-keV X-rays. Some of the FE hysteresis loops show distortion at 5 Mrad(Si). The type and degree of distortion are dependent on the polarization state and/or the applied field during irradiation. Preliminary results indicate that a fraction of the radiation-induced damage can be removed simply by cycling the FE capacitor with a 20-kHz square wave. The amount of damage removed is dependent upon the radiation conditions View full abstract»

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  • Variation in proton-induced upsets rates from large solar flares using an improved SEU model

    Publication Year: 1990 , Page(s): 1947 - 1952
    Cited by:  Papers (11)
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    Proton integral flux measurements during solar energetic particle (SEP) events, from the CPME instrument onboard the IMP-8 satellite, and the proton detector on the GOES-7 satellite, are utilized to calculate proton-induced single-event upset (SEU). An improved two-parameter SEU cross section model is used for three RAM devices. The log of the 239 actual RAM upsets on the TDRS-1 satellite during the October 19, 1989 SEP event allowed a comparison between the recorded number of upsets/chip per day and those predicted based on the GOES-7 data, the two-parameter model, and the shielding distribution curve View full abstract»

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  • Investigation of single event upset subject to protons of intermediate energy range [RAM]

    Publication Year: 1990 , Page(s): 1953 - 1960
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (508 KB)  

    Nuclear reaction models to reproduce p+Si nuclear reactions precisely in the incident proton energy region of below 50 MeV are investigated, and a computer code based on exciton models is developed. Si irradiation experiments in the intermediate energy region were performed to measure energy deposited by p+Si nuclear reactions with two totally depleted Si detectors in face-to-face arrangement. Coincident signals were analyzed by a two-dimensional pulse height analyzer. This method is shown to be effective in discriminating signals of contaminating particles. The experimental observations are in good agreement with the computed predictions. The single-event upset (SEU) cross section of the 93L422 (RAM) is also compared with the calculated values View full abstract»

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  • Radiation effects on fluorinated field oxides and associated devices

    Publication Year: 1990 , Page(s): 2026 - 2032
    Cited by:  Papers (5)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (512 KB)  

    Fluorine has been introduced into the LOCOS field oxide by high-energy (2-MeV) F implantation and subsequent annealing at 950°C for 60 min. Improved radiation hardness of the field oxide and its associated device parameters was observed. N-channel MOSFETs isolated by the fluorinated oxide exhibit a lower radiation-induced source-drain leakage current. This is attributed to the smaller density of radiation-induced positive oxide charge in the fluorinated field oxide compared to its control. This is consistent with experimental results showing that threshold voltage shifts of the field-oxide FETs are smaller than their control. In addition, the radiation-induced leakage currents of reverse biased n+p-junction diodes fabricated with the F implantation process are suppressed, suggesting that the generation of interface traps at the gate SiO2-Si and the field SiO2-Si interfaces is also reduced in the fluorinated devices View full abstract»

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  • Experimental and simulation study of the effects of cosmic particles on CMOS/SOS RAMs

    Publication Year: 1990 , Page(s): 1855 - 1860
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (484 KB)  

    The existence of a charge multiplication effect in CMOS/SOS RAM circuits, as reported by J. Rollins (1987), is confirmed. Shorter channel lengths and higher power supply voltages caused the ratio, M , of upset charge to deposited charge to increase. As a result of this multiplication factor, actual devices are more likely to upset than expected from an analysis of only the collected charge. A mixed-mode simulator was used to model the charge collection process. The results showed that the M factor is a very fluid number which is dependent on minority carrier lifetime, drain voltage, and the switching dynamics of the cell in addition to the dependence on mobility ratio and channel length reported by Rollins. Parasitic bipolar gain at high injection levels appears to be the primary mechanism allowing collected charge to be greater than deposited charge. The simulator and experimental data show that, as floating body static memory transistors are down scaled, the particle energy needed to upset the cell is reduced because of the enhanced parasitic bipolar gain effect as well as a reduction in the node capacitance View full abstract»

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  • Effect of radiation-induced charge on 1/f noise in MOS devices

    Publication Year: 1990 , Page(s): 1696 - 1702
    Cited by:  Papers (35)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (468 KB)  

    The 1/f noise in MOS transistors is measured as a function of gate and drain bias, total ionizing dose, and postirradiation biased annealing time. The transistors tested varied in size, radiation hardness, and process technology. The radiation-induced 1/f noise correlates strikingly with the oxide trap charge through irradiation and anneal, but not with interface-trap charge, for frequencies up to 10 kHz. This implies that oxide trapped charge is the predominant factor which leads to the increased 1/f noise in irradiated MOS devices View full abstract»

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  • Particle-induced spatial dark current fluctuations in focal plane arrays

    Publication Year: 1990 , Page(s): 1784 - 1791
    Cited by:  Papers (26)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (644 KB)  

    An analytic calculation which describes the pixel-to-pixel variation in the particle-induced dark current distribution of a focal plane array is developed. The most important contributions to the dark current variance are shown to be the variations in the number of primary interactions, the energies of the primary recoils produced, and the charge emission from radiation-induced defects due to that electric field distribution. Microdosimetry theory provides a general approach for calculating the dark current variance for any incident particle for which the moments of the recoil spectrum are known and is shown to predict the dark current response successfully for neutrons and protons View full abstract»

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  • Imaging charge-coupled device (CCD) transient response to 17 and 50 MeV proton and heavy-ion irradiation

    Publication Year: 1990 , Page(s): 1876 - 1885
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (808 KB)  

    The results of irradiating a high-resolution, large-area, silicon charge-coupled device (CCD) imaging array (Kodak KAF-1400) with controlled low fluxes of collimated monoenergetic (17- and 50-MeV) protons and selected heavy ions are presented. The CCD response was measured at several angles of incidence, from normal to 70° off normal, and at several azimuthal angles. The transient response events are recorded and analyzed to infer the effective charge collection depth of the CCD. Selected individual proton-induced events are analyzed for their two-dimensional spatial amplitude, and the results are compared to a charge collection model which included contributions from both the pixel depletion and diffusion volumes for the geometry (pixel size and spacing) and thickness (depletion depth and epitaxial layer thickness) of this CCD View full abstract»

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  • Total-dose radiation-induced degradation of thin film ferroelectric capacitors

    Publication Year: 1990 , Page(s): 1703 - 1712
    Cited by:  Papers (21)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (808 KB)  

    The radiation hardness of thin-film PbZryTi1-y O3 (PZT) ferroelectric capacitors is explored. Ferroelectric capacitors were irradiated using X-ray and Co-60 sources to dose levels up to 16 Mrad(Si). The capacitors were characterized for their memory properties both before and after irradiation. The radiation hardness was process dependent. Three out of four processes resulted in capacitors that showed less than 30% radiation-induced degradation in retained polarization charge and remnant polarization after irradiating to 16 Mrad(Si). On the other hand, one of the processes showed significant radiation-induced degradation in retained polarization charge and remanent polarization at dose levels above 1 Mrad(Si). A model for simulating the observed degradation is developed. The model indicates that the data are consistent with trapping of radiation-induced charge in the ferroelectric material. The radiation hardness levels indicate that ferroelectric devices can be fabricated that can survive radiation exposures well in excess of 10 Mrad(Si) View full abstract»

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  • The behaviour of measured SEU at low altitude during periods of high solar activity [spacecraft memories]

    Publication Year: 1990 , Page(s): 1938 - 1946
    Cited by:  Papers (24)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (584 KB)  

    The UoSAT-2 spacecraft, launched in 1984 into a polar orbit at an altitude of 700 km, has a number of systems which have been observed to experience single-event upsets at significant rates. During the year 1989, several solar flare events occurred which elevated the upset rates at high latitudes. The October 19 event, in particular, resulted in very high high-latitude upset rates. The data are separated and analyzed, deriving upset rates for the various memory devices under quiet cosmic-ray, South Atlantic anomaly, and solar flare conditions. The results of the heavy ion and proton testing of UoSAT memories undertaken in order to compare predictions and observations are presented View full abstract»

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  • Estimation of proton upset rates from heavy ion test data [ICs]

    Publication Year: 1990 , Page(s): 1961 - 1965
    Cited by:  Papers (21)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (372 KB)  

    A simple method of calculating the proton upset rates from heavy ion test data is presented. Given the approximations made, particularly in fitting a curve to the experimental data, the error made in determining the upset rate can be as large as four or six. It is clear from this model that ICs with heavy ion thresholds >10 MeV/(mg/cm2) will probably not upset with protons. In critical applications ICs with LET thresholds less than 10 MeV/(mg/cm 2) should be tested with protons, or at the minimum careful heavy ion test data should be taken in the low LET regions (for heavy ion upset considerations as well as proton upset) View full abstract»

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  • Radiation induced defects in CVD-grown 3C-SiC

    Publication Year: 1990 , Page(s): 1732 - 1738
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (568 KB)  

    Radiation-induced defects in 3C-SiC epitaxially grown by a chemical vapor deposition method were studied with the electron spin resonance (ESR) technique. A 15-line ESR spectrum was observed in 2-MeV proton and 1-MeV electron irradiated 3C-SiC when the magnetic field was applied parallel to the <100> axis. This spectrum, T1, which has an isotropic g-value of 2.0029±0.0001, was interpreted by simultaneous hyperfine interactions of a paramagnetic electron with the surrounding 13C at four carbon sites and 29Si at 12 silicon sites. The T1 spectrum appeared to arise from a point defect at a silicon site. The observed hyperfine interactions with neighboring 13C and 29Si nuclei are discussed in terms of a simple molecular-orbital treatment of the defect View full abstract»

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  • Total-dose characterization of a high-performance radiation-hardened 1.0-μm CMOS sea-of-gates technology

    Publication Year: 1990 , Page(s): 2089 - 2096
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (584 KB)  

    A radiation-hardened CMOS sea-of-gates technology with 1.0-μm geometry is developed which is fully compatible with commercial technologies. Total-dose and postirradiation effects are investigated in detail on transistors and circuits designed on a 2K-gate test chip. The data show that this technology is radiation hardened up to a total dose of 1 Mrad(SiO2) and may be functional at 10 Mrad(SiO2 ). Moreover, using a simple analytic model for switching of CMOS circuits, it is shown that the changes in circuit performance are well correlated with those in transistor characteristics View full abstract»

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  • Modeling the anneal of radiation-induced trapped holes in a varying thermal environment

    Publication Year: 1990 , Page(s): 1682 - 1689
    Cited by:  Papers (81)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (708 KB)  

    The anneal of radiation-induced trapped holes in MOS transistors is found to be thermally activated. A quantitative, physical model based on thermal emission and tunneling is developed. It accurately predicts the anneal of radiation-induced trapped holes in constant or time-varying thermal environments. Data are presented which quantitatively verify the accuracy of the model for temperatures between 25 and 160°C. This model provides the basis for developing accurate quantitative screens for the rebound failure mechanism View full abstract»

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  • Single event induced transients in I/O devices: a characterization

    Publication Year: 1990 , Page(s): 1974 - 1980
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (448 KB)  

    The results of single-event upset (SEU) testing performed to evaluate the parametric transients, i.e. amplitude and duration, in several I/O devices, and the impact of these transients are discussed. The failure rate of these devices is dependent on the susceptibility of interconnected devices to the resulting transient change in the output of the I/O device. This failure rate, which is a function of the susceptibility of the interconnected device as well as the SEU response of the I/O device itself, may be significantly different from an upset rate calculated without taking these factors into account. The impact at the system level is discussed by way of an example View full abstract»

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  • A quantitative investigation of hydrogen in the metal-oxide-silicon system using NRA

    Publication Year: 1990 , Page(s): 1658 - 1669
    Cited by:  Papers (2)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (916 KB)  

    The present state of development in the application of resonant nuclear reaction analysis to the direct measurement of hydrogen concentration profiles throughout the metal-oxide-silicon system is presented. Detection limits of less than 1018 cm-3 (1012 cm-2) as well as a depth resolution of better than 10 nm are obtained. Limitations of the technique in the study of changes in the hydrogen profiles caused by ex-situ irradiation are discussed. It is shown that the method is sensitive enough to provide the first clear measurements of the hydrogen distribution in bulk SiO2 (500-1000 ppma). Evidence is provided which indicates that the dominating source of hydrogen for the bulk SiO2 may not be the oxidation process; rather, the surface layer formed through exposure to air, between the oxidation and evaporation processes, may, in some cases, determine the bulk level. Some initial data are presented, directly relating the hydrogen content in MOS structures and the measured changes in interface and oxide charges following 60Co irradiation View full abstract»

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  • Interpretation of high voltage solar array discharge experiments

    Publication Year: 1990 , Page(s): 2120 - 2127
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    High-voltage operation of photovoltaic power sources in low earth orbit is limited by the probability of discharges in the array. Laboratory experiments were conducted to characterize these discharges. A model is proposed that suggests that experiments conducted to date have measured transients related to the discharging of the solar cell cover glass as a result of a discharge rather than the discharge itself. A system analysis approach is adopted to model the discharge transient. It is found that the experimental transients could be modeled as the decharging of the solar cell cover glass through the adhesive resistance. Ion current collection by the interconnects after the discharge could be modeled as an equivalent inductor. The predictions of this model are shown to be in excellent agreement with the data View full abstract»

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  • High-frequency annealing effects on ionizing radiation response of MOSFET

    Publication Year: 1990 , Page(s): 1670 - 1676
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (464 KB)  

    The effects of high-frequency AC bias on the ionizing radiation response of MOSFETs are studied. Radiation-induced interface traps are annealed out during irradiation and postirradiation annealing when an AC bias is applied with a zero offset voltage. In addition, the recovery of 40-MHz-biased devices agreed with that of 860-MHz-biased ones for the same total number of alternating cycles of AC gate bias voltage. It is concluded that an alternating transition between inversion and accumulation caused by high-frequency AC bias is responsible, and the total number of transition cycles may be relevant for the annealing of radiation-induced interface traps View full abstract»

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  • Heavy ion total fluence effects in GaAs devices

    Publication Year: 1990 , Page(s): 2065 - 2070
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (456 KB)  

    Heavy ion radiation effects were studied in GaAs FETs, monolithic microwave integrated circuits (MMICs), and high-electron-mobility transistors (HEMTs). Degradation of GaAs FETs, MMICs, and HEMTs occurred at about 109 cm-2 for 14.5-MeV Si and at 1012 cm-2 for 2-MeV protons. Carrier removal resulting from displacement damage in the active channel, or in the doping layer in the case of HEMTs, is the primary reason for the decrease in drain current and gain and the increase in noise figure. Decrease in mobility is also a contributing factor. HEMTs were found to degrade in gain and noise figure at higher levels of irradiation, primarily because of the initial higher dopant concentration in the AlGaAs N+ doping layer View full abstract»

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  • Experiments and modeling of the photocurrent response of GaAs MESFETs

    Publication Year: 1990 , Page(s): 2050 - 2057
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (688 KB)  

    1-μm technology GaAs MESFETs were exposed to a transient radiation environment at the Rensselaer Gaerttner linear accelerator laboratory and modeled by computer simulation using a modified version of the PISCES-IIB semiconductor device simulation code and the TRIGSPICE circuit simulation code. The MESFETs were tested in steady-state conditions, with short (20-ns) radiation pulses and with short pulses on devices that had received a prior dose of gamma, neutron, or neutron-plus-gamma irradiation. Parasitic bipolar action was observed in the short pulse testing in unexposed devices. Previously unreported transient failure was observed in the neutron preirradiated devices only. The threshold for this failure is consistent with the level of severity of prior irradiation. steady-state photocurrent and the parasitic bipolar transistor are modeled and explained on the basis of physical mechanisms View full abstract»

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