Spectroscopy of Impurities and Complex Defects in Silicon in Zlectric and Microwave Fields

1987 ◽  
Vol 104 ◽  
Author(s):  
M. Godlewski ◽  
H. Weman ◽  
F. P. Wang ◽  
B. Monemar ◽  
W. M. Chen ◽  
...  
Keyword(s):  
Electric Fields ◽  
Cyclotron Resonance ◽  
Impact Ionization ◽  
Simultaneous Recording ◽  
Pulsed Dc ◽  
Dc Excitation ◽  
Pl Intensity ◽  
Optically Detected ◽  
High Frequency Ac ◽  
The Impact

ABSTRACTWe report a detailed study of the photoluminescence (PL) intensity of bound excitons (BE:s) in silicon, related to shallow impurities and deep complex defects, as a function of DC and high frequency AC (9GHz) electric fields. Two experimental approaches are presented. The first involves a simultaneous recording of PL and photocurrent under pulsed DC excitation. The second utilizes the optically detected cyclotron resonance (ODCR) technique, which allows detection of cyclotron resonance (CR) via the resonancetransition- induced changes of BE PL intensity. The mechanism responsible for the PL changes is shown to be the impact ionization of BE:s by hot free carriers. Effects of sample inhomogeneities in these experiments are also discussed.

scholarly journals The Barkhausen Method to Investigate Powerful Processes during Action of Piezoelectric Igniters

2020 ◽  
Vol 26 (3) ◽  
pp. 358-362
Author(s):  
Linas ARDARAVIČIUS ◽  
Skirmantas KERŠULIS ◽  
Oleg KIPRIJANOVIČ ◽  
Česlovas ŠIMKEVIČIUS ◽  
Steponas AŠMONTAS
Keyword(s):  
Electric Fields ◽  
High Voltage ◽  
Impact Ionization ◽  
Domain Switching ◽  
Practical Importance ◽  
Total Duration ◽  
High Amplitude ◽  
High Voltage Pulse ◽  
Pulse Generation ◽  
The Impact

The Barkhausen method is proposed to clarify the cause of radiation of electromagnetic (EM) pulses during high voltage pulse generation by piezoelectric igniters (PIs). Wide bandwidth of the experimental setup was narrowed for a simultaneous registration of electric and detected EM pulses by a two-channel oscilloscope. The PI was loaded on a high ohmic resistance and high voltage pulses of 8 – 17 kV amplitude and up to 150 ms in total duration were registered. These pulses contained a series of short pulses called Barkhausen type pulses. Duration of these pulses having the relatively high amplitude was 30 – 40 ns. The registration revealed that the radiating EM pulse series corresponded to Barkhausen type pulse series. Short non-radiating negative pulses appearing during the saturated voltage growth were also observed and they had relaxation tails. The analysis showed that the EM pulses are caused as a result of domain switching with high voltage spikes at the PZT cylinders bases, where high electric fields are created. The activity of these switchings weakens when the “age” of PIs increases. The non-radiated pulses resulted from fast internal screening processes in the volume of the cylinders, accompanied by the impact ionization. The increase of the saturation and PI’s “age” causes lengthening of the relaxation tails. The results of practical importance for PIs in monitoring systems are placed. It is concluded that the Barkhausen method in wideband configuration is a convenient experimental arrangement for investigation of powerful processes in ferro-piezoelectric ceramics.

DARK CURRENTS AND IMPACT IONIZATION COEFFICIENTS IN THE InP-InGaAsP DOUBLE HETEROSTRUCTURES

2006 ◽  
Vol 20 (29) ◽  
pp. 4929-4936
Author(s):  
M. OZER ◽  
M. AHMETOGLU ◽  
N. APRAILOV
Keyword(s):  
Electric Fields ◽  
Impact Ionization ◽  
Reverse Current ◽  
Tunneling Current ◽  
Double Heterostructures ◽  
Wide Range ◽  
Direct Energy ◽  
Ionization Coefficients ◽  
Dark Currents ◽  
The Impact

The dependence of reverse-biased leakage current on both voltage and temperature for InP - In x Ga 1-x As y P 1-y DH (double heterostructures) has been analyzed. We find that at the whole of the temperature range and at a wide range of reverse bias voltages, the reverse current varies exponentially with applied voltage, indicating that the band-to-band tunneling current mechanism prevails. An agreement is obtained between theory and experimental results. The tunneling current becomes substantial at peak junction electric fields as low as 105 V/m due to the small direct energy gaps and small effective masses of the structures tested. The process of breakdown in the investigated structures was of the avalanche type. The impact ionization coefficients in In x Ga 1-x As y P 1-y have been experimentally determined for composition x=0.68.

Low-voltage Avalanche Breakdown in AlGaN Multi-quantum Wells

2006 ◽  
Vol 955 ◽  
Author(s):  
Shengkun Zhang ◽  
X. Zhou ◽  
Wubao Wang ◽  
R. R. Alfano ◽  
A. M. Dabiran ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Electric Fields ◽  
Impact Ionization ◽  
Low Voltage ◽  
Defect Density ◽  
Control Sample ◽  
Avalanche Breakdown ◽  
Ionization Coefficient ◽  
The Impact ◽  
Injection Modes

ABSTRACTIn this work, electro-luminescence (EL) of a AlGaN p-i-n diode have been investigated in both avalanche and injection modes. The active i-region of the diode consists of Al0.1Ga0.9N/Al0.15Ga0.85N MQWs. Strong interband luminescence from the Al0.1Ga0.9N active layers was observed when operating the device in both avalanche and injection modes. The threshold voltage for avalanche breakdown is as low as 9 V. This indicates that the impact ionization coefficient of electrons is greatly enhanced in these Al0.1Ga0.9N/Al0.15Ga0.85N MQWs comparing to AlGaN bulk materials. Polarization-induced electric fields in the Al0.1Ga0.9N well layers are believed to be responsible for the enhancement of the ionization coefficient. In a control sample that has higher defect density, the electroluminescence was dominated by long-wavelength emissions, which results from impact ionizations of the defect levels.

IMPACT IONIZATION AND HIGH FIELD EFFECTS IN WIDE BAND GAP SEMICONDUCTORS

2001 ◽  
Vol 11 (02) ◽  
pp. 511-524 ◽  
Author(s):  
M. REIGROTZKI ◽  
J. R. MADUREIRA ◽  
A. KULIGK ◽  
N. FITZER ◽  
R. REDMER ◽  
...  
Keyword(s):  
Electric Fields ◽  
High Field ◽  
Impact Ionization ◽  
Electron Distribution Function ◽  
Wide Band ◽  
Ionization Rate ◽  
Wide Bandgap ◽  
Bandgap Semiconductors ◽  
Impact Ionization Rate ◽  
The Impact

Impact ionization plays a crucial role for electron transport in wide-bandgap semiconductors at high electric fields. Therefore, a realistic band structure has to be used in calculations of the microscopic scattering rate, as well as high field quantum corrections such as the intercollisional field effect. Here we consider both, and evaluate the impact ionization rate for wide-bandgap materials such as ZnS. A pronounced softening of the impact ionization threshold is obtained, as found earlier for materials like Si and GaAs. This field dependent impact ionization rate is included within a full-band ensemble Monte Carlo simulation of high field transport in ZnS. Although the impact ionization rate itself is strongly affected, little effect is observed on measurable quantities such as the impact ionization coefficient or the electron distribution function itself.

Dendritic Growth Failure of a Mesa Diode

1997 ◽  
Author(s):  
P. Singh ◽  
V. Cozzolino ◽  
G. Galyon ◽  
R. Logan ◽  
K. Troccia ◽  
...  
Keyword(s):  
Electric Fields ◽  
Dendritic Growth ◽  
Silicon Oxide ◽  
Impact Ionization ◽  
Electron Tunneling ◽  
Growth Failure ◽  
Side Wall ◽  
Oxide Interface ◽  
Band Bending ◽  
Cross Section Area

Abstract The time delayed failure of a mesa diode is explained on the basis of dendritic growth on the oxide passivated diode side walls. Lead dendrites nucleated at the p+ side Pb-Sn solder metallization and grew towards the n side metallization. The infinitesimal cross section area of the dendrites was not sufficient to allow them to directly affect the electrical behavior of the high voltage power diodes. However, the electric fields associated with the dendrites caused sharp band bending near the silicon-oxide interface leading to electron tunneling across the band gap at velocities high enough to cause impact ionization and ultimately the avalanche breakdown of the diode. Damage was confined to a narrow path on the diode side wall because of the limited influence of the electric field associated with the dendrite. The paper presents experimental details that led to the discovery of the dendrites. The observed failures are explained in the context of classical semiconductor physics and electrochemistry.

scholarly journals Peculiarities of Neurostimulation by Intense Nanosecond Pulsed Electric Fields: How to Avoid Firing in Peripheral Nerve Fibers

2021 ◽  
Vol 22 (13) ◽  
pp. 7051
Author(s):  
Vitalii Kim ◽  
Emily Gudvangen ◽  
Oleg Kondratiev ◽  
Luis Redondo ◽  
Shu Xiao ◽  
...  
Keyword(s):  
Side Effects ◽  
Electric Fields ◽  
Pulsed Electric Fields ◽  
Opposite Polarity ◽  
Nerve Fibers ◽  
High Rate ◽  
Excitation Threshold ◽  
Compound Action Potentials ◽  
Supramaximal Stimulation ◽  
The Impact

Intense pulsed electric fields (PEF) are a novel modality for the efficient and targeted ablation of tumors by electroporation. The major adverse side effects of PEF therapies are strong involuntary muscle contractions and pain. Nanosecond-range PEF (nsPEF) are less efficient at neurostimulation and can be employed to minimize such side effects. We quantified the impact of the electrode configuration, PEF strength (up to 20 kV/cm), repetition rate (up to 3 MHz), bi- and triphasic pulse shapes, and pulse duration (down to 10 ns) on eliciting compound action potentials (CAPs) in nerve fibers. The excitation thresholds for single unipolar but not bipolar stimuli followed the classic strength–duration dependence. The addition of the opposite polarity phase for nsPEF increased the excitation threshold, with symmetrical bipolar nsPEF being the least efficient. Stimulation by nsPEF bursts decreased the excitation threshold as a power function above a critical duty cycle of 0.1%. The threshold reduction was much weaker for symmetrical bipolar nsPEF. Supramaximal stimulation by high-rate nsPEF bursts elicited only a single CAP as long as the burst duration did not exceed the nerve refractory period. Such brief bursts of bipolar nsPEF could be the best choice to minimize neuromuscular stimulation in ablation therapies.

scholarly journals Engineered tunneling layer with enhanced impact ionization for detection improvement in graphene/silicon heterojunction photodetectors

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Jun Yin ◽  
Lian Liu ◽  
Yashu Zang ◽  
Anni Ying ◽  
Wenjie Hui ◽  
...  
Keyword(s):  
High Performance ◽  
Impact Ionization ◽  
Low Cost ◽  
Atomic Layer ◽  
Light Illumination ◽  
Insulation Material ◽  
Defect States ◽  
Uv Illumination ◽  
Layer Deposition ◽  
The Impact

AbstractHere, an engineered tunneling layer enhanced photocurrent multiplication through the impact ionization effect was proposed and experimentally demonstrated on the graphene/silicon heterojunction photodetectors. With considering the suitable band structure of the insulation material and their special defect states, an atomic layer deposition (ALD) prepared wide-bandgap insulating (WBI) layer of AlN was introduced into the interface of graphene/silicon heterojunction. The promoted tunneling process from this designed structure demonstrated that can effectively help the impact ionization with photogain not only for the regular minority carriers from silicon, but also for the novel hot carries from graphene. As a result, significantly enhanced photocurrent as well as simultaneously decreased dark current about one order were accomplished in this graphene/insulation/silicon (GIS) heterojunction devices with the optimized AlN thickness of ~15 nm compared to the conventional graphene/silicon (GS) devices. Specifically, at the reverse bias of −10 V, a 3.96-A W−1 responsivity with the photogain of ~5.8 for the peak response under 850-nm light illumination, and a 1.03-A W−1 responsivity with ∼3.5 photogain under the 365 nm ultraviolet (UV) illumination were realized, which are even remarkably higher than those in GIS devices with either Al2O3 or the commonly employed SiO2 insulation layers. This work demonstrates a universal strategy to fabricate broadband, low-cost and high-performance photo-detecting devices towards the graphene-silicon optoelectronic integration.

scholarly journals Restraining Surface Charge Accumulation and Enhancing Surface Flashover Voltage through Dielectric Coating

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 750
Author(s):  
Jixing Sun ◽  
Sibo Song ◽  
Xiyu Li ◽  
Yunlong Lv ◽  
Jiayi Ren ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Electric Field ◽  
Electric Fields ◽  
Transition Process ◽  
Metallic Particle ◽  
Particle Charging ◽  
Insulating Surfaces ◽  
Surface Flashover ◽  
Charging Time ◽  
The Impact

A conductive metallic particle in a gas-insulated metal-enclosed system can charge through conduction or induction and move between electrodes or on insulating surfaces, which may lead to breakdown and flashover. The charge on the metallic particle and the charging time vary depending on the spatial electric field intensity, the particle shape, and the electrode surface coating. The charged metallic particle can move between the electrodes under the influence of the spatial electric field, and it can discharge and become electrically conductive when colliding with the electrodes, thus changing its charge. This process and its factors are mainly affected by the coating condition of the colliding electrode. In addition, the interface characteristics affect the particle when it is near the insulator. The charge transition process also changes due to the electric field strength and the particle charging state. This paper explores the impact of the coating material on particle charging characteristics, movement, and discharge. Particle charging, movement, and charge transfer in DC, AC, and superimposed electric fields are summarized. Furthermore, the effects of conductive particles on discharge characteristics are compared between coated and bare electrodes. The reviewed studies demonstrate that the coating can effectively reduce particle charge and thus the probability of discharge. The presented research results can provide theoretical support and data for studying charge transfer theory and design optimization in a gas-insulated system.

Temperature Dependence of Hole Impact Ionization Coefficient in 4H-SiC Photodiodes

2009 ◽  
Vol 615-617 ◽  
pp. 311-314 ◽  
Author(s):  
W.S. Loh ◽  
J.P.R. David ◽  
B.K. Ng ◽  
Stanislav I. Soloviev ◽  
Peter M. Sandvik ◽  
...  
Keyword(s):  
Phonon Scattering ◽  
Impact Ionization ◽  
Positive Temperature Coefficient ◽  
Positive Temperature ◽  
Different Temperatures ◽  
Ionization Coefficients ◽  
Increasing Temperature ◽  
The Impact ◽  
Good Agreement ◽  
Ionization Rates

Hole initiated multiplication characteristics of 4H-SiC Separate Absorption and Multiplication Avalanche Photodiodes (SAM-APDs) with a n- multiplication layer of 2.7 µm were obtained using 325nm excitation at temperatures ranging from 300 to 450K. The breakdown voltages increased by 200mV/K over the investigated temperature range, which indicates a positive temperature coefficient. Local ionization coefficients, including the extracted temperature dependencies, were derived in the form of the Chynoweth expression and were used to predict the hole multiplication characteristics at different temperatures. Good agreement was obtained between the measured and the modeled multiplication using these ionization coefficients. The impact ionization coefficients decreased with increasing temperature, corresponding to an increase in breakdown voltage. This result agrees well with the multiplication characteristics and can be attributed to phonon scattering enhanced carrier cooling which has suppressed the ionization process at high temperatures. Hence, a much higher electric field is required to achieve the same ionization rates.

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