Zero bias resonant tunnel Schottky contact diode for wide-band direct detection

The wide band gap of SiC semiconductor devices constitutes a serious challenge to build good Ohmic contacts on the surface of the p-type material. This is reflected in the numerical analysis of ”realistic” devices, where we have to cope with serious problems, such as a shifting threshold voltage, reduced forward conductivity, and no noticeable conductivity modulation by minority carrier injection from p+-emitters, in matching measured data with simulation results, as a consequence of the significant impact of non-ideal poor Ohmic contacts. In this work, we used a Schottky contact model together with a barrier tunneling model, instead of common ideal Ohmic contact model, to simulate the non-ideal Ohmic contact on SiC MPS diodes. Based on this approach, the I-V characteristics of real Ohmic contacts can be reproduced in high-fidelity simulations, providing us physical insight of the observed operational behavior.

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Optoelectronic matrix switching

Canadian Journal of Physics ◽

10.1139/p89-069 ◽

1989 ◽

Vol 67 (4) ◽

pp. 389-393 ◽

Cited By ~ 4

Author(s):

R. I. MacDonald

Keyword(s):

Cross Talk ◽

Electromagnetic Coupling ◽

Integrated Control ◽

Forward Bias ◽

Wide Band ◽

Optical Signal ◽

Current Status ◽

Design Matrix ◽

Hybrid Technique ◽

Zero Bias

Because cross talk from electromagnetic coupling increases with frequency, it is difficult to design matrix switches for high-frequency electronic signals. Signals on optical carriers are easier to isolate but more difficult to switch. A hybrid technique exploiting passive optical-signal distribution and switching by optoelectronic effects shows good promise for high isolation matrices to handle signals in the dc to 10 GHz range. The key elements for such optoelectronic switches are optical detectors that have switchable sensitivity.Initial efforts in optoelectronic switching used silicon diode detectors and forward bias to establish the off-state. Recent work has turned primarily to photoconductors fabricated in GaAs or other compound semiconductors. Such photoconductors can have very wide response bandwidths and have the advantage of a zero-bias off-state. Efforts have also been made to develop bipolar detectors that do not need forward bias for the off-state.Experimental work has progressed to the demonstration of complete matrices capable of switching up to eight incoming signals to as many outgoing lines, at bandwidths up to 500 MHz and cross-talk levels below 50 dB. Results for individual switching devices give promise of matrices for many tens of lines and bandwidths to several gigahertz. Monolithic integration of GaAs photoconductor switch arrays has been demonstrated, and work progresses to include integrated control devices and amplifiers.Matrix switches of large dimension and very large bandwidth are expected to have significant applications in areas other than communications switching. In particular, such matrices can be used to set up patterns of delay and signal recombination, using fibre delay lines, to provide rapidly selectable wide-band delay for phasing and other applications, or for wide-band tapped delay-line filters that can be reconfigured rapidly.A review of the current status in optoelectronic matrix switching is given.

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89 GHz zero‐bias Schottky detector for direct detection radiometry in European satellite programme MetOp‐SG

Electronics Letters ◽

10.1049/el.2014.0222 ◽

2014 ◽

Vol 50 (8) ◽

pp. 606-608 ◽

Cited By ~ 10

Author(s):

M. Hoefle ◽

A. Penirschke ◽

O. Cojocari ◽

T. Decoopman ◽

M. Trier ◽

...

Keyword(s):

Direct Detection ◽

Zero Bias ◽

European Satellite

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A COMPARISON OF ULTRA WIDE BAND CONVENTIONAL AND DIRECT DETECTION RADAR FOR CONCEALED HUMAN CARRIED EXPLOSIVES DETECTION

Progress In Electromagnetics Research Letters ◽

10.2528/pierl13012508 ◽

2013 ◽

Vol 39 ◽

pp. 37-47 ◽

Cited By ~ 4

Author(s):

Stuart William Harmer ◽

Nicholas John Bowring ◽

Nacer Ddine Rezgui ◽

David Andrews

Keyword(s):

Direct Detection ◽

Wide Band ◽

Explosives Detection ◽

Ultra Wide Band

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Capacitance Characteristics and Breakdown Mechanism of AlGaN/GaN Metal–Semiconductor–Metal Varactors and their Anti-Surge Application

Crystals ◽

10.3390/cryst10040292 ◽

2020 ◽

Vol 10 (4) ◽

pp. 292

Author(s):

Chien-Fu Shih ◽

Yu-Li Hsieh ◽

Liann-Be Chang ◽

Ming-Jer Jeng ◽

Zi-Xin Ding ◽

...

Keyword(s):

Signal Transmission ◽

Schottky Contact ◽

Wide Band ◽

High Electron ◽

Wide Band Gap ◽

Breakdown Mechanism ◽

Metal Semiconductor Metal ◽

Voltage Dependent ◽

Protection Circuits ◽

Surge Protection

The AlGaN/GaN materials with a wide band gap, high electron mobility, and high breakdown voltage are suitable for manufacturing high-power and high-frequency electronic devices. In this study, metal Schottky contact electrodes of different dimensions are prepared on AlGaN/GaN wafers to fabricate metal–semiconductor–metal (MSM) varactors. Voltage-dependent capacitance and breakdown voltages of the varactors are measured and studied. The corresponding breakdown mechanisms of varactors with different electrode gaps are proposed. Furthermore, an anti-surge application using GaN-based MSM varactors in a signal transmission module is demonstrated, and its surge suppression capability is shown. We believe that our study will be beneficial in developing surge protection circuits for RF applications.

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Detection of fast neutrons from D–T nuclear reaction using a 4H–SiC radiation detector

International Journal of Modern Physics Conference Series ◽

10.1142/s2010194516602350 ◽

2016 ◽

Vol 44 ◽

pp. 1660235 ◽

Cited By ~ 2

Author(s):

Bohumir Zatko ◽

Andrea Sagatova ◽

Katarina Sedlackova ◽

Vladimir Necas ◽

Frantisek Dubecky ◽

...

Keyword(s):

Nuclear Reaction ◽

Epitaxial Layer ◽

Elevated Temperatures ◽

Detection Efficiency ◽

Radiation Detector ◽

Schottky Contact ◽

Wide Band ◽

Fast Neutrons ◽

Hydrogen Atoms ◽

Detector Material

The particle detector based on a high purity epitaxial layer of 4H–SiC exhibits promising properties in detection of various types of ionizing radiation. Due to the wide band gap of 4H–SiC semiconductor material, the detector can reliably operate at room and also elevated temperatures. In this work we focused on detection of fast neutrons generated the by D–T (deuterium–tritium) nuclear reaction. The epitaxial layer with a thickness of 105 [Formula: see text]m was used as a detection part. A circular Schottky contact of a Au/Ni double layer was evaporated on both sides of the detector material. The detector structure was characterized by current-voltage and capacitance-voltage measurements, at first. The results show very low current density (<0.1 nA/cm[Formula: see text] at room temperature and good homogeneity of free carrier concentration in the investigated depth. The fabricated detectors were tested for detection of fast neutrons generated by the D–T reaction. The energies of detected fast neutrons varied from 16.0 MeV to 18.3 MeV according to the acceleration potential of deuterons, which increased from 600 kV up to 2 MV. Detection of fast neutrons in the SiC detector is caused by the elastic and inelastic scattering on the silicon or carbide component of the detector material. Another possibility that increases the detection efficiency is the use of a conversion layer. In our measurements, we glued a HDPE (high density polyethylene) conversion layer on the detector Schottky contact to transform fast neutrons to protons. Hydrogen atoms contained in the conversion layer have a high probability of interaction with neutrons through elastic scattering. Secondary generated protons flying to the detector can be easily detected. The detection properties of detectors with and without the HDPE conversion layer were compared.

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