Abstract: We fabricate pn-junction diode on p-type 4H-SiC(0001), in which n-type region is formed
by N ion implantation at room temperature (total dose: 2.4 x 1015 /cm2, thickness: 300 nm) and
subsequently annealed for 5 min using electron bombardment annealing system (EBAS). The
root-mean-square (RMS) surface roughness and sheet resistance (Rs) for N ion implanted region,
annealed at 1900 oC is estimated to be 0.7 nm and 940 4/sq., respectively. The alloyed Ni ohmic
contact to N ion implanted layer, annealed at 1900 oC, shows the contact resistance (Rc) of
8.3 x 10-5 4cm2. The forward drop voltage at 100 A/cm2 and on-resistance of mesa-type pn junction
diode is estimated to be 3.1 V and 1.3x10-2 4cm2. The reverse bias leakage current of that is
2.2 x 10-5 A/cm2 at 100 V. It is demonstrated that EBAS is able to apply for the fabrication of
Abstract: 4H-SiC p-i-n diodes were fabricated on epitaxial layers grown by Sublimation Epitaxy in
Vacuum (SEV) and were evaluated for microwave power switching applications. Full electrical
characterization (C-V, DC I-Vs, reverse recovery characteristics, low and high power microwave
testing) has been performed. The results showed that SEV-grown SiC material is suitable for
bipolar device fabrication. A doping higher than 1019 cm-3 for the p-type contact layer and lower
than 1016 cm-3 for the n-type base layer is necessary to demonstrate microwave p-i-n diodes with
similar performance as the ones fabricated on commercially available CVD-grown material.
Abstract: Zener diodes are widely used in electrical barriers to protect equipment operating in a
potentially explosive atmosphere. Although normally not conducting, the zeners must have a high
power rating so that their junction temperature meets safety factors when shunting the maximum
fuse current. This often requires two or three lower voltage commercial zeners connected in series.
Silicon carbide diodes have much higher thermal conductivity and maximum allowed junction
temperature, so it should be possible to use one SiC zener in the place of two or three commercial
diodes and/or allow use of higher fuse ratings. Low voltage SiC Zener diodes were fabricated and
tested to evaluate potential benefits of their application as a component of intrinsically safe barriers.
The diodes demonstrated mixed avalanche-tunnel breakdown at reverse bias voltages of 23 V with
positive temperature coefficients of breakdown voltages of about 0.4 mV/°C. The diodes with mesa
area of 4×10-4cm2 had maximum DC Zener current of 1.2 A and were capable of operating at
ambient temperatures up to 500°C.
Abstract: The detector structures based on Al ion-implanted p+-n junctions in 4H-SiC have been
manufactured and tested at temperatures up to 170oC by α-particles with energies of 3.9 and 5.5
MeV. Structural peculiarities of thin Al high dose ion implanted layers before and after short high
temperature activation annealing were studied by combination of Rutherford back
scattering/channeling spectrometry and cross-sectional transmission electron microscopy. The
detector structures fabricated on this thin ion implanted p+-n junctions operated in the temperature
range of 16-170 oC with reproducible stable spectrometric characteristics. The charge collection
efficiency and the energy resolution of detectors improved with rising temperature up to 170 oC,
that was obtained in SiC detectors for the first time.
Abstract: The fabrication of high sensitive diodes array is very attractive for spectroscopic and
astronomical UV imaging applications, particularly when visible light rejection is required. Wide
band gap materials are excellent candidates for UV “visible blind” detection. In this paper, we
demonstrate an array of Schottky UV-diodes on 4H-SiC with a single pixel area of about 1.44 mm2
and a total area of about 29 mm2. The Schottky photodiodes are based on the pinch-off surface
effect, the front electrode being an interdigit Ni2Si contact that allows the direct light exposure of
the optically active device area. For the proposed array, the optically active area is about the 48 %
of total area. The single pixel dark current was below 0.1 nA up to –50 V and a fabrication yield of
about 90 % was observed. The external quantum efficiency of the proposed array exhibits a peak of
45 % at the 289 nm wavelength and a visible rejection ratio > 4 ×103.
Abstract: Silicon Carbide has proven its relevance for various MEMS and sensors devices
applications. This paper presents the fabrication and the first test results of 3C-SiC electrostatic
resonators actuated by applying a combination of AC and DC voltages. The recipe used for the
fabrication has taken the advantage of the starting material, 3C-SiC grown on Si, which allows us to
use the Si substrate as sacrificial layer to release the structures. Resonators have been fabricated by a
two-step process, combining RIE ICP etching with HF wet etching. Resonators have been
successfully electrostatically actuated in air-ambient condition. The resonance frequencies were
clearly identified, although capacitive current created by actuation was not detected.
Abstract: Avalanche photodiodes (APDs) based on 4H-SiC are excellent candidates to replace
PMTs in the UV, particularly for harsh environment applications. Here, we report on dark current
analysis of 4H-SiC APDs with separate absorption and multiplication regions. Detailed analysis of
the leakage current as a function of device size showed that for a given device design, the bulk
leakage component is dominant at U>600V, while surface leakage is dominant at U<600V. Electron
beam induced current was also used to establish a correlation between leakage current and major
types of defects in the substrate. There were two types of dislocations that could be easily
distinguished in the images, including threading (spots) and basal plane (comet-like) dislocations.
Using image processing software, densities of threading dislocations as well as basal plane
dislocations were obtained and correlated with leakage currents of the corresponding APDs. The
results suggest a strong effect of threading dislocations on dark current. Densities of basal plane
dislocations were very similar in all devices tested suggesting that a role of basal plane dislocations
was not dominant in leakage current of the APDs.
Abstract: SiC is a biocompatible material and a candidate as a transducer for biosensors. Here we
have investigated the possibility to functionalize SiC with biomolecules. We have also processed
very simple devices and performed electrical characterization. Double polished SiC samples with a
C-face substrate and Si-face low doped epilayer have been functionalized on both sides. The SiC
was first treated by HF in order to remove the native oxide, partly successful on the Si-face side but
probably not on the C-face side. MPTMS, 3-mercaptopropyl trimethoxysilane, was chosen as the
biomolecule since it has both a silanol group to be used as an anchoring group to the substrate and a
thiol group available for further linking possibilities. The functionalization was evaluated by XPS,
contact angle experiments, AFM and electrical measurements. The MPTMS molecules attached
with the thiol (or sulphur containing) group pointing out from the surface on both faces of the SiC.
Interesting differences between the two faces are however revealed by the analysis.
Abstract: The charge collection efficiency (ССЕ) of SiC-detectors preliminarily irradiated with
8 MeV protons at a fluence of 1014 cm-2 has been studied. Nuclear spectrometric techniques with
5.4 MeV α-particles were employed to test the detectors. The concentration of primarily created
defects was estimated to be 4×1016 cm-3. A strong compensation of SiC was observed, which
allowed connection of the structure in the forward mode. The experimental data obtained were
processed using a simple two-parameter model of signal formation. The model makes it possible to
separate the contributions of electrons and holes to the ССЕ. An additional irradiation at a fluence
of 2×1014 cm-2 reduced the ССЕ value by a factor of 2 and gave rise to polarization. The latter
indicates that radiation-induced centers are not only actively involved in carrier localization (with a
decrease in the lifetime), but also in transformation of the electric field within the detector.
Abstract: Due to research results have already been published