Plasma current multiplication at high current levels

1980 ◽  
Vol 58 (1) ◽  
pp. 98-104 ◽  
Author(s):  
W. T. Shmayda ◽  
P. C. Stangeby
Keyword(s):  
Current Density ◽  
Dominant Role ◽  
Gas Discharge ◽  
Experimental Results ◽  
Current Gain ◽  
Plasma Current ◽  
High Current ◽  
Discharge Device ◽  
Gas Pressures

The plasma current multiplier, PCM, is a simple gas discharge device which has the capability of amplifying small cathode currents to large anode currents. Experimental results are presented for the current gain of a PCM operating on argon and covering a range of gas pressures and current levels. It is found that gain increases with pressure and decreases with current density. A theory is presented which explains the experimental observations. Gas rarefaction due to heating by the discharge electrons is found to play a dominant role in high current PCM operation.

scholarly journals Power lateral pnp transistor operating with high current density in irradiated voltage regulator

2013 ◽  
Vol 28 (2) ◽  
pp. 146-157 ◽  
Author(s):  
Vladimir Vukic ◽  
Predrag Osmokrovic
Keyword(s):  
Current Density ◽  
High Current Density ◽  
Positive Influence ◽  
Radiation Hardness ◽  
Current Gain ◽  
Voltage Regulator ◽  
Interface Traps ◽  
High Current ◽  
Oxide Trapped Charge ◽  
Trapped Charge

The operation of power lateral pnp transistors in gamma radiation field was examined by detection of the minimum dropout voltage on heavily loaded low-dropout voltage regulators LM2940CT5, clearly demonstrating their low radiation hardness, with unacceptably low values of output voltage and collector-emitter voltage volatility. In conjunction with previous results on base current and forward emitter current gain of serial transistors, it was possible to determine the positive influence of high load current on a slight improvement of voltage regulator LM2940CT5 radiation hardness. The high-current flow through the wide emitter aluminum contact of the serial transistor above the isolation oxide caused intensive annealing of the positive oxide-trapped charge, leading to decrease of the lateral pnp transistor's current gain, but also a more intensive recovery of the small-signal npn transistors in the control circuit. The high current density in the base area of the lateral pnp transistor immediately below the isolation oxide decreased the concentration of negative interface traps. Consequently, the positive influence of the reduced concentration of the oxide-trapped charge on the negative feedback reaction circuit, together with the favourable effect of reduced interface traps concentration, exceeded negative influence of the annealed oxide-trapped charge on the serial pnp transistor's forward emitter current gain.

The study on reliability of Ni-coated graphene doped SAC305 lead-free composite solders under high current-density stressing

2019 ◽  
Vol 31 (4) ◽  
pp. 261-270
Author(s):  
Guang Chen ◽  
Jiqiang Li ◽  
Xinwen Kuang ◽  
Yaofeng Wu ◽  
Fengshun Wu
Keyword(s):  
Solder Joint ◽  
Current Density ◽  
Composite Solder ◽  
Solder Joints ◽  
Experimental Results ◽  
Lead Free ◽  
Cathode Side ◽  
High Current ◽  
Sac305 Solder ◽  
Content Type

Purpose The purpose of this paper is to investigate the effect of nickel-plated graphene (Ni-GNS) on the microstructure and mechanical properties of 96.5Sn3Ag0.5Cu (SAC305) lead-free solder joints before and after an electro-migration (EM) experiment. Design/methodology/approach In this paper, SAC305 solder alloy doped with 0.1 Wt.% Ni-GNS was prepared via the powder metallurgy method. A U-shaped sample structure was also designed and prepared to conduct an EM experiment. The EM experiment was carried out with a current density of 1.5 × 104 A/cm2. The microstructural and mechanical evolutions of both solder joints under EM stressing were comparatively studied using SEM and nanoindentation. Findings The experimental results showed that for the SAC305 solder, the interfacial intermetallic compounds (IMC) formulated a protrusion with an average height of 0.42 µm at the anode after 360 h of EM stressing; however, despite this, the surface of the composite solder joint was relatively smooth. During the stressing period, the interfacial IMC on the anode side of the plain SAC305 solder showed a continuous increasing trend, while the IMC at the cathode presented a decreasing trend for its thickness as the stressing time increased; after 360 h of stressing, some cracks and voids had formed on the cathode side. For the SAC305/ Ni-GNS composite solder, a continuous increase in the thickness of the interfacial IMC was found on both the anode and cathode side; the growth rate of the interfacial IMC at the anode was higher than that at the cathode. The nanoindentation results showed that the hardness of the SAC305 solder joint presented a gradient distribution after EM stressing, while the hardness data showed a relatively homogeneous distribution in the SAC305/ Ni-GNS solder joint. Originality/value The experimental results showed that the Ni-GNS reinforcement could effectively mitigate the EM behavior in solder joints under high current stressing. Specifically, the Ni particles that plated the graphene sheets can work as a fixing agent to suppress the diffusion and migration of Sn and Cu atoms by forming Sn-Cu-Ni IMC. In addition, the nanoidentation results also indicated that the addition of the Ni-GNS reinforcement was very helpful in maintaining the mechanical stability of the solder joint. These findings have provided a theoretical and experimental basis for the practical application of this novel composite solder with high current densities.

Reliability of InP-based HBTs at High Current Density

2009 ◽  
Vol 1195 ◽  
Author(s):  
Yoshino Fukai
Keyword(s):  
Current Density ◽  
Refractory Metal ◽  
High Speed ◽  
High Current Density ◽  
High Reliability ◽  
Critical Time ◽  
Surface Recombination ◽  
Contact Layer ◽  
Current Gain ◽  
High Current

AbstractInP-based HBTs for ultrahigh speed optical communications systems operation at over 40 GHz require a long-term stability under high current injection conditions, such as current densities of 2 or 5 mA/μm2. We achieved high reliability by suppressing surface recombination and emitter-metal-related crystalline degradation.Changes in the electric properties of devices due to temperature and bias stress were evaluated. The reduction in DC current gain due to surface recombination had the activation energy of 1.7 eV without current density dependence, and the lifetime of HBTs for this degradation mode is predicted to be over 1×108 hours at 125°C. The emitter metal diffusion and disruption of uniformity of the atomic composition were observed by transmission electron microscopy and energy dispersive X-ray spectroscopy in HBTs with the conventional Ti/Pt/Au emitter, whereas suppression of those degradations was observed in HBTs with refractory metal of Mo and W. The emitter resistance was estimated to evaluate the contact layer degradation. The critical time was one order larger for HBTs with refractory metal than for HBTs with conventional metal. The activation energies for resistance increases were 2.0 and 1.65 eV for the current density of 2 and 5 mA/μm2, respectively, for all types of emitter electrodes.The effectiveness of the refractory metal electrode for improving device reliability was confirmed, especially in high-current-density operation, which is essential for applying InP HBTs in high-speed ICs.

scholarly journals Pseudospark ion diodes

1987 ◽  
Vol 5 (4) ◽  
pp. 581-587 ◽  
Author(s):  
W. Bauer ◽  
A. Brandelik ◽  
A. Citron ◽  
H. Ehrler ◽  
E. Halter ◽  
...  
Keyword(s):  
High Voltage ◽  
Current Density ◽  
Streak Camera ◽  
Gas Discharge ◽  
Ion Beams ◽  
High Current ◽  
Axially Symmetric ◽  
Target Interaction ◽  
Theoretical Results ◽  
A Current

The Pseudospark is an axially symmetric, high-voltage gas discharge operating at pressures below 100 Pa. It is capable of producing pinched high current ion beams. Streak camera photographs of the operation of this discharge reveal that a pinch with a diameter of ∼1 mm occurs in the diode. The beam then expands to about 1 to 10 mm in a distance of 12 cm. The beam-target interaction shows a UV-emitting plasma corresponding to protons with a main energy of 100 keV and a current density of about 16 kA/cm2. Initial theoretical results for the pseudospark are given.

Controlled gas-discharge device with cold hollow cathode

1971 ◽  
Vol 7 (3) ◽  
pp. 61 ◽  
Author(s):  
I.I. Aksenov ◽  
V.A. Belous ◽  
S.A. Smirnov
Keyword(s):  
Hollow Cathode ◽  
Gas Discharge ◽  
Discharge Device
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