Silicon Detectors Highly Compensated by Neutron Induced Deep Levels for Low Energy X-RAY Detection

1993 ◽  
Vol 302 ◽  
Author(s):  
Zheng Li ◽  
H. W. Kraner
Keyword(s):  
Neutron Radiation ◽  
Low Noise ◽  
Deep Levels ◽  
High Resistivity ◽  
Silicon Detectors ◽  
Obvious Effect ◽  
X Ray ◽  
Shaping Time ◽  
Resistive Feedback ◽  
P Type

ABSTRACTFast neutron radiation damage in silicon results in defect levels which are predominantly acceptor-like at low fluences and may be used to compensate high resistivity ntype material to create very high effective resisitivity material. Compensated material to the order of Neff below 1011/cm3 enables depletion of diode thicknesses ≥ 1mm at reasonable biases (<100V), yielding diodes of reasonable area and capacitance<1 pF which are suitable for low noise applications such as X-ray spectrometry. Although exposure to fluences of this order will greatly increase the generation current and require cooling, most high resolution X-ray spectrometry systems are routinely operated at reduced temperature to achieve low noise operation of the front end electronics. Silicon p+ /n− /n+ implanted devices (area ≤0.25 cm2) made on high resistivity FZ silicon have been irradiated by 1 MeV neutrons to fluences of a few times 1012 n/cm2. Thick n− substrates (d=630 μm and 1000 μm) were used to achieve detector capacitances εεo/d in the range of 1 pF. After a neutron fluence of ϕn=2.9×1012 n/cm2, the total depletion of a p+/n−/n+ detector, 1040 μm thick and an area of 0.1 cm2, is reached at about V=50 Volts, with a Cd of 1 pF and a neutron induced leakage current of about 300 nA at room temperature. A total depletion of an 680 μm thick detector was reached after the fluence of 2-5×1012 n/cm2 at a voltage of 20 volts, and the capacitance of a 0.25 cm2 diode is 4.5 pF The resistivities of the compensated detector substrates are in the range of 100 K Ω-cm, and are not inverted to “p” type. The trapping of collected charge by neutron induced deep levels is modeled and simulated, and is found to be less than a few percent; with no obvious effect on peak shape. Using a resistive feedback preamplifier of modest noise contribution (225 eV), resolution of the Mn K∝ X-ray was 255 eV (FWHM) with 3 μsec shaping time constants. Other effects of uncollected charge will be discussed and comparisons between this type of detectors and Li-drift silicon detectors will be made.

Implant Isolation Mechanisms in GaAs, AlGaAs, InP and InGaAs

1988 ◽  
Vol 144 ◽  
Author(s):  
S. J. Pearton ◽  
C. R. Abernathy ◽  
W. S. Hobson ◽  
A. E. Von Neida
Keyword(s):  
Target Material ◽  
Interesting Case ◽  
Deep Levels ◽  
High Resistivity ◽  
Doping Density ◽  
Deep Acceptor ◽  
P Type ◽  
Ion Species ◽  
Isolation Mechanisms ◽  
Stable Material

ABSTRACTWe have investigated the thermal stability of high resistivity regions introduced by ion bombardment of GaAs, AlGaAs, InP and InGaAs. For low doses in which the ion species density is below that of the doping density in the target material, we obtain the usual damage-related compensation in which deep levels created by the bombardment trap the charge carriers. By this method one creates material with resistivities around 108 Ω/□ (n- or p-type GaAs and AlGaAs, p-type InP), around 106 Ω/□ (n-type InP) or around 105 Ω/□ (n-type InGaAs or p-type InGaAs), with a return of the initial resistivity after elevated temperature annealing (∼600°C for GaAs and AIGaAs, ∼500°C for InP and InGaAs). The more interesting case is the use of higher dose implants of species which create chemical deep levels. This occurs for O in n-type AlGaAs where O creates a deep acceptor (Ec-0.49 eV), and Fe in n-type InP and InGaAs, where it is also a deep acceptor. When the concentration of these species exceeds the doping density in the material, the bombarded regions retain their high resistivity even after high temperature annealing (> 1000°C for GaAs and AIGaAs, >850°C for InP and InGaAs). The case of O in GaAs appears to represent a third mechanism; it creates thermally stable material only in the case of Be-doped GaAs, suggesting an ion-pairing reaction.

The Growth of Porous Layer on Resistive P-Type Silicon in HF/Ethylene Glycol under Illumination

2005 ◽  
Vol 480-481 ◽  
pp. 217-224 ◽  
Author(s):  
N. Chiboub ◽  
F. Bellal ◽  
N. Gabouze ◽  
S. Sam
Keyword(s):  
Ethylene Glycol ◽  
High Frequency ◽  
Pore Diameter ◽  
Characteristic Size ◽  
High Resistivity ◽  
Photoelectrochemical Etching ◽  
Impedance Measurements ◽  
X Ray ◽  
Anodization Time ◽  
P Type

In the present work, a photoelectrochemical etching method had been performed on resistive p-type Si (100) to eliminate the instability attributed to the high resistivity of substrate comparing to that of electrolyte. The anodization of p-type Si with resistivity ranging from 10 Ωcm to 30 kΩcm was done in HF/ethylene glycol. The resistivity of electrolyte was experimentally determinated by high frequency impedance measurements. As anodization proceeds structures of increasing characteristic size are formed then a steady state is reached, where macropore grow parallel. It shows that pore diameter increases with increasing HF concentration. Whereas, under laser He-Ne irradiation both of nanopores and macropores are observed during the anodization. The nanoporous layer showed to be varying with the light intensity and the anodization time. The proprieties of the porous silicon were investigated by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) and energy-dispersive X-ray (EDX).

Study of Deep Levels by Admittance Spectroscopy in High Resistivity P-Type 6H-SiC Single Crystals

1995 ◽  
Vol 378 ◽  
Author(s):  
A. O. Evwaraye ◽  
S. R. Smith ◽  
W. C. Mitchel
Keyword(s):  
Single Crystals ◽  
Deep Levels ◽  
High Resistivity ◽  
Admittance Spectroscopy ◽  
Donor Level ◽  
Decay Kinetics ◽  
Exponential Form ◽  
Conductance Peak ◽  
P Type ◽  
Kinetics Of

AbstractDeep levels in high resistivity p-type 6H-SiC has been studied using optical admittance spectroscopy ( OAS ). Besides the conductance peak due to the band to band transitions, there are three conductance peaks in the spectra of most of the samples. The conductance peak due to the vanadium donor (0/+) level at EV+ 1.55 eV is identified. The persistent photoconductance (PPC) at this defect was also studied. The decay kinetics of the PPC follow the stretched exponential form. The potential barrier against recapture of carriers was determined to be 220 meV for the vanadium donor level.

A Low Noise Silicon Detector Preamplifier System for Room Temperature X-Ray Spectroscopy

1993 ◽  
Vol 302 ◽  
Author(s):  
G. Bertuccio ◽  
A. Pullia
Keyword(s):  
High Resolution ◽  
Room Temperature ◽  
Silicon Detector ◽  
Low Noise ◽  
High Resistivity ◽  
Charge Amplifier ◽  
X Ray ◽  
High Resistivity Silicon ◽  
Ultra Low Noise ◽  
Low Capacitance

ABSTRACTThe design and performances of a system for high resolution X-ray spectroscopy are presented. The detector is a low capacitance diode built on high resistivity silicon. The signal preamplification is made by means of an ultra-low noise charge amplifier of new conception. Presently the system exhibits an equivalent noise charge of 61 r.m.s. electrons at 297 K and 32 r.m.s. electrons at 223 K. It is shown how an improvement down to 30 r.m.s. electrons at room temperature is expected employing an integrated transistor on the detector chip.

scholarly journals Low-noise X-ray PIN photodiodes made of perovskite single crystals by Solution-processed doped epitaxial growth

2020 ◽  
Author(s):  
Xin Wang ◽  
Yubing Xu ◽  
Yuzhu Pan ◽  
Yuwei Li ◽  
Ji Xu ◽  
...  
Keyword(s):  
Epitaxial Growth ◽  
Single Crystals ◽  
Dark Current ◽  
Low Noise ◽  
Detection Sensitivity ◽  
Electron Hole ◽  
Solution Processed ◽  
X Ray ◽  
P Type ◽  
Pin Photodiodes

Abstract X-ray photodiodes made of metal halide perovskites (MHPs) which directly convert X-ray photons into electron-hole pairs have shown advantages in low-cost and high X-ray detection sensitivity. However, devices fabricated by spin-coating and evaporation methods suffer from high traps density near poor interfacial layers (n-type/intrinsic and p-type/intrinsic) which lead to high dark current and noise current under large reverse bias. In this work, solution-processed doped epitaxial growth is employed to limit these traps through epitaxially growing n-type MHPs (bismuth-doped) and p-type MHPs (silver-doped) on opposite faces of intrinsic CH3NH3PbBr2.5Cl0.5 MHP single crystals. Through energy structure design, effective electron/hole blocking layers could decrease the noise and dark current, these X-ray PIN photodiodes work under a large external electrical field, which enables a state-of-art response speed (fall) of 750 ns and a lowest detectable dose rate of 17.7 nGys-1(40 kVp). This work will motivate new strategies to fabricate high-performance devices based on perovskites using solution-processed methods. These founding also explore a new generation of low dose and high dynamic X-ray detectors based on MHPs.

scholarly journals Characterization of Chromium Compensated GaAs Sensors with the Charge-Integrating JUNGFRAU Readout Chip by Means of a Highly Collimated Pencil Beam

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1550
Author(s):  
Dominic Greiffenberg ◽  
Marie Andrä ◽  
Rebecca Barten ◽  
Anna Bergamaschi ◽  
Martin Brückner ◽  
...  
Keyword(s):  
Low Noise ◽  
State University ◽  
Noise Performance ◽  
X Ray ◽  
A Value ◽  
Resolution Capability ◽  
Sensor Properties ◽  
Pixel Pitch ◽  
Lower Noise

Chromium compensated GaAs or GaAs:Cr sensors provided by the Tomsk State University (Russia) were characterized using the low noise, charge integrating readout chip JUNGFRAU with a pixel pitch of 75 × 75 µm2 regarding its application as an X-ray detector at synchrotrons sources or FELs. Sensor properties such as dark current, resistivity, noise performance, spectral resolution capability and charge transport properties were measured and compared with results from a previous batch of GaAs:Cr sensors which were produced from wafers obtained from a different supplier. The properties of the sample from the later batch of sensors from 2017 show a resistivity of 1.69 × 109 Ω/cm, which is 47% higher compared to the previous batch from 2016. Moreover, its noise performance is 14% lower with a value of (101.65 ± 0.04) e− ENC and the resolution of a monochromatic 60 keV photo peak is significantly improved by 38% to a FWHM of 4.3%. Likely, this is due to improvements in charge collection, lower noise, and more homogeneous effective pixel size. In a previous work, a hole lifetime of 1.4 ns for GaAs:Cr sensors was determined for the sensors of the 2016 sensor batch, explaining the so-called “crater effect” which describes the occurrence of negative signals in the pixels around a pixel with a photon hit due to the missing hole contribution to the overall signal causing an incomplete signal induction. In this publication, the “crater effect” is further elaborated by measuring GaAs:Cr sensors using the sensors from 2017. The hole lifetime of these sensors was 2.5 ns. A focused photon beam was used to illuminate well defined positions along the pixels in order to corroborate the findings from the previous work and to further characterize the consequences of the “crater effect” on the detector operation.

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