共查询到20条相似文献,搜索用时 312 毫秒
1.
A Fully Integrated, Low Noise and Low Power BiCMOS Front-end Readout System for Capacitive Detectors 总被引:1,自引:0,他引:1
Chaoying-Christine Guo Philippe Schmitt Grzegorz Deptuch Yongcai-Yann Hu 《Analog Integrated Circuits and Signal Processing》2001,28(3):211-223
Bipolar transistors are interesting for low noise front-end readout systems when high speed and low power consumption are required. This paper presents a fully integrated, low noise front-end design for the future Large Hadron Collider (LHC) experiments using the radiation hard SOI BiCMOS process. In the present prototype, the input-referred Equivalent Noise Charge (ENC) of 990 electrons (rms) for 12 pF detector capacitance with a shaping time of 25 ns and power consumption of 1.4 mW/channel has been measured. The gain of this front-end is 90 mV/MIP (Minimum Ionisation Particle: 1
fC) with non-linearity of less than 3% and linear input dynamic range is
MIP. These results are obtained at room temperature and before irradiation. The measurements after irradiations by high intensity pion beam with an integrated flux of
pions/cm2 are also presented in this paper. 相似文献
2.
Creep behavior of eutectic Sn-Cu lead-free solder alloy 总被引:3,自引:0,他引:3
Tensile creep behavior of precipitation-strengthened, tin-based eutectic Sn-0.7Cu alloy was investigated at three temperatures
ranging from 303–393 K. The steady-state creep rates cover six orders of magnitude (10−3−10−8 s−1) under the stress range of σ/E=10−4−10−3. The initial microstructure reveals that the intermetallic compound Cu6Sn5 is finely dispersed in the matrix of β-Sn. By incorporating a threshold stress, σ
th, into the analysis, the creep data of eutectic Sn-Cu at all temperatures can be fitted by a single straight line with a slope
of 7 after normalizing the steady-state creep rate and the effective stress, indicating that the creep rates are controlled
by the dislocation-pipe diffusion in the tin matrix. So the steady-state creep rate,
, can be expressed as
exp
, where Qc is the activation energy for creep, G is the temperature-dependent shear modulus, b is the Burgers vector, R is the universal
gas constant, T is the temperature, σ is the applied stress, A is a material-dependent constant, and
, in which σ
OB is the Orowan bowing stress, and kR is the relaxation factor.
An erratum to this article is available at . 相似文献
3.
The transport times τ(P) and the mean free paths of magnetoexcitons in a quantum well and of spatially direct and indirect magnetoexcitons in coupled
quantum wells in a random potential produced by thickness fluctuations of the quantum wells or a random distribution of impurity
centers in quantum wells (P is the magnetic momentum of an exciton) are calculated. The function τ(P) is nonmonotonic, but as the distance D between the quantum wells increases, the maximum τ
max(P) gradually vanishes in the presence of scattering by surface terraces. As the magnetic field (H) increases, τ(0) decreases as
for
is the magnetic length) and as 1/H
2 for D≫l. The behavior of the computed values of τ for large H agrees qualitatively with the experimental data. The mean free path length of a magnetoexciton exhibits at P≠0 a maximum whose magnitude decreases as the parameter D/l increases.
Fiz. Tekh. Poluprovodn. 32, 596–601 (May 1998) 相似文献
4.
CORDIC-based algorithms to compute cos
and
are proposed. The implementation requires a standard CORDIC module plus a module to compute the direction of rotation, this being the same hardware required for the extended CORDIC vectoring, recently proposed by the authors [T. Lang and E. Antelo, IEEE Transactions on Computers, vol. 47, no. 7, 1998, pp. 736–749.]. Although these functions can be obtained as a special case of this extended vectoring, the specific algorithm we propose here presents two significant improvements: (1) it uses the same datapath width as the standard CORDIC, even when t has 2n bits (to achieve a granularity of 2–n for the whole range). In contrast, the extended vectoring unit requires about 2n bits. (2) no repetitions of iterations are needed (the extended vectoring needs some repetitions). The proposed algorithm is compatible with the extended vectoring and, in contrast with previous implementations, the number of iterations and the delay of each iteration are the same as for the conventional CORDIC algorithm. 相似文献
5.
Interfacial reactions of Y and Er thin films on both (111)Si and (001)Si have been studied by transmission electron microscopy
(TEM). Epitaxial rare-earth (RE) silicide films were grown on (111)Si. Planar defects, identified to be stacking faults on
planes with 1/6
displacement vectors, were formed as a result of the coalescence of epitaxial silicide islands. Double-domain epitaxy was
found to form in RE silicides on (001)Si samples resulting from a large lattice mismatch along one direction and symmetry
conditions at the silicide/(001)Si interfaces. The orientation relationships are [0001]RESi2−x//
Si,
RESi2−x//(001)Si and [0001]RESi2−x/
Si,
RESi2−x//(001)Si. The density of staking faults in (111) samples and the domain size in (001) samples were found to decrease and
increase with annealing temperature, respectively. 相似文献
6.
This paper considers the problem of constructing feedback stabilizing controllers for the wave operator on
n (more generally AR systems determined by a hyperbolic operator). In order to accomplish this, it must first clarify the notion of an input-output structure on a distributed system, as well as what it means to interconnect two such systems. Both these notions are shown to be consequences of a structure which generalizes the standard causal structure of lumped systems determined by the flow of time. Given this apparatus, the paper then constructs feedback controllers which stabilize the wave equation along directions given by a proper cone in
n. 相似文献
7.
Orientation dependent etching of photolithographically patterned
GaP was investigated using solutions of HCl:CH3COOH:H2O2. The pattern was prepared using standard ultraviolet lithography and was a two-dimensional grid with an 18 μm repeat, consisting
of 15 μm squares separated by 3 μm spaces. The mask sides were aligned along the
and
directions. Under appropriate etching conditions, high quality arrays of pyramids were prepared. These pyramids were defined
by
,
and
facets. It was shown that the etching process depended on the degree of solution aging after initial mixing. For a freshly
prepared solution, the etching rate showed an inverse dependence on time. For short etching times (below 5 min), an intermediate
etching profile was followed, while for long times (greater than 5 min) etching was kinetically controlled. We demonstrated
that controlled etching at extremely low rates (0.1–0.5 μm/min) is feasible with this new approach. 相似文献
8.
The ability of a parallel algorithm to make efficient use of increasing computational resources is known as its scalability. In this paper, we develop four parallel algorithms for the 2-dimensional Discrete Wavelet Transform algorithm (2-D DWT), and derive their scalability properties on Mesh and Hypercube interconnection networks. We consider two versions of the 2-D DWT algorithm, known as the Standard (S) and Non-standard (NS) forms, mapped onto P processors under two data partitioning schemes, namely checkerboard (CP) and stripped (SP) partitioning. The two checkerboard partitioned algorithms
(Non-standard form, NS-CP), and as
(Standard form, S-CP); while on the store-and-forward-routed (SF-routed) Mesh and Hypercube they are scalable as
(NS-CP), and as
(S-CP), respectively, where M
2 is the number of elements in the input matrix, and (0,1) is a parameter relating M to the number of desired octaves J as
. On the CT-routed Hypercube, scalability of the NS-form algorithms shows similar behavior as on the CT-routed Mesh. The Standard form algorithm with stripped partitioning (S-SP) is scalable on the CT-routed Hypercube as M
2 = (P
2), and it is unscalable on the CT-routed Mesh. Although asymptotically the stripped partitioned algorithm S-SP on the CT-routed Hypercube would appear to be inferior to its checkerboard counterpart S-CP, detailed analysis based on the proportionality constants of the isoefficiency function shows that S-SP is actually more efficient than S-CP over a realistic range of machine and problem sizes. A milder form of this result holds on the CT- and SF-routed Mesh, where S-SP would, asymptotically, appear to be altogether unscalable. 相似文献
9.
A 900 MHz low-power CMOS bandpassamplifier suitable for the applications of RFfront-end in wireless communication receiversis proposed and analyzed. In this design, thetemperature compensation circuit is used tostabilize the amplifier gain so that theoverall amplifier has a good temperaturestability. Moreover, the compact tunablepositive-feedback circuit is connected to theintegrated spiral inductor to generate thenegative resistance and enhance its
value. The simple diode varactor circuit isadopted for center-frequency tuning. These twoimproved circuits can reduce the powerdissipation of the amplifier. An experimentalchip fabricated by 0.5 mdouble-poly-double-metal CMOS technologyoccupies a chip area of
; chip area. The measuredresults have verified the performance of thefabricated CMOS bandpass amplifier. Under a2-V supply voltage, the measured quality factoris tunable between 4.5 and 50 and the tunablefrequency range is between 845 MHz and 915 MHz. At
, the measured
is 20 dB whereas thenoise figure is 5.2 dB in the passband. Thegain variation is less than 4 dB in the rangeof 0–80°C. The dc powerdissipation is 35 mW. Suitable amplifier gain,low power dissipation, and good temperaturestability make the proposed bandpass amplifierquite feasible in RF front-endapplications. 相似文献
10.
Charalampos Kapnistis Konstantinos Misiakos Nikos Haralabidis 《Analog Integrated Circuits and Signal Processing》2001,27(1-2):39-49
A charge sensitive readout chain has been designed and fabricated in acommercially available 0.8 m CMOS technology. The readout chain is optimizedfor pixel detectors measuring soft X-ray energies up to 20 KeV. In the first modean analog signal proportional to input charge is generated and processed in realtime. In the second mode a peak-and-hold operation is enabled and therelevant signal is processed in later time. This dual mode of operation iscontrolled by an external digital signal. The readout chain consists of a chargeamplifier, a shaper, an operational amplifier which can either operate as avoltage amplifier or a peak detector and an output buffer. Its area is
. The gain at the shaper output is 378 mv/fC, theENC is 16
rms at 160 nsec shaping time. The overall gainis 557 mV/fC, the ENC is
rms with 240 nsec peaking timeand 1.4 sec recovery time. The overall power dissipation is 1.5 mWatt with aload capacitance of 25 pF. 相似文献
11.
Masakazu Katsuno Noboru Ohtani Tatsuo Fujimoto Hirokatsu Yashiro 《Journal of Electronic Materials》2005,34(1):91-95
The effect of off-orientation growth has been investigated in terms of stacking fault formation during physical vapor transport
(PVT) growth of silicon carbide (SiC) single crystals on the (11
0) seed crystal surface. Occurrence of stacking fault formation is largely dependent on the direction of off-orientation,
and basal plane stacking fault density is significantly reduced by growing the crystals on a (11
0) seed crystal off-oriented toward 〈0001〉. The density of the basal plane stacking faults rapidly decreases from 100–150
cm−1 to ∼10 cm−1 as the degree of off-orientation is increased from 0 to 10 deg. The results are interpreted in the framework of microscopic
facet formation during PVT growth, and the introduction of off-orientation of seed crystal is assumed to prevent (01
0) and (10
0) microfacet formation on the (11
0) growing surface through modification of the surface growth kinetics and to suppress the stacking fault formation.
An erratum to this article is available at . 相似文献
12.
Seoyong Ha Noel T. Nuhfer Gregory S. Rohrer Marc de Graef Marek Skowronski 《Journal of Electronic Materials》2000,29(7):L5-L8
Transmission electron microscopy (TEM) and KOH etching have been used to study the dislocation structure of 4H SiC wafers
grown by physical vapor transport. A new type of threading dislocation arrays was observed. Rows of etch pits corresponding
to dislocation arrays were observed in vicinity of micropipes, misoriented grains and polytypic inclusions at the periphery
of the boules and extended along the
directions. Plan view conventional and high resolution TEM showed that the arrays consisted of dislocations threading along
the c-axis with Burgers vectors having edge components of the a/3
type. The Burgers vectors were parallel to the corresponding arrays. The dislocation arrays were interpreted as slip bands
formed by dislocation glide in the prismatic slip system
of hexagonal SiC during post-growth cooling. 相似文献
13.
Mohammed Ahmed Ghouse 《The Journal of VLSI Signal Processing》1993,5(1):57-74
New algorithms for the DFT and the 2-dimensional DFT are presented. The DFT and the 2-dimensional DFT matrices can be expressed as the Kronecker product of DFT matrices of smaller dimension. These algorithms are synthesized by combining the efficient factorization of the Kronecker product of matrices with the highly hardware efficient recursive implementation of the smaller DFT matrices, to yield these algorithms. The architectures of the processors implementing these algorithms consist of 2-dimensional grid of processing elements, have temporal and spatial locality of connections. For computing the DFT of sizeN or for the 2D DFT of sizeN=N
1 byN
1, these algorithms require 2N multipliers and adders, take approximately
computational steps for computing a transform vector, and take approximately
computation steps between the computation of two successive transform vectors. 相似文献
14.
Hao Lee Weidong Yang Peter C. Sercel A. G. Norman 《Journal of Electronic Materials》1999,28(5):481-485
We have determined the shape of InAs quantum dots using reflection high energy electron diffraction. Our results indicate
that self-assembled InAs islands possess a pyramidal shape with {136} bounding facets. This shape is characterized by C2v
symmetry and a parallelogram base, which is elongated along the
direction. Cross-sectional transmission electron microscopy images taken along the [110] and
directions as well as atomic force microscopy images strongly support the {136} shape. Furthermore, polarization-resolved
photoluminescence spectra show strong in-plane anisotropy, with emission predominantly polarized along the
direction, consistent with the proposed quantum dot shape. 相似文献
15.
In this paper we investigate new Fourier series with respect to orthonormal families of directed cycles
, which occur in the graph of a recurrent stochastic matrixP. Specifically, it is proved thatP may be approximated in a suitable Hilbert space by the Fourier series
. This approach provides a proof in terms of Hilbert space of the cycle decomposition formula for finite stochastic matricesP. 相似文献
16.
Feng Wu Shai Zamir Boris Meyler Joseph Salzman Yuval Golan 《Journal of Electronic Materials》2003,32(1):23-28
Transmission electron microscopy (TEM), atomic force microscopy (AFM), and photoluminescence (PL) spectroscopy were used in
order to study the microstructure and optical properties of GaN films grown by metal-organic chemical vapor deposition (MOCVD)
on c-plane sapphire by lateral confined epitaxy (LCE). In this method, the substrate is etched prior to growth to form uniform
mesas separated by trenches for laterally restricting growth area. As previously observed for LCE GaN on Si(111), the density
of threading dislocations was significantly reduced in the areas close to the edge of mesas due to the lateral propagation
of the dislocations. Hence, the overall material quality improves with decreasing mesa size, which is consistent with the
observed increase in photoluminescence band edge peak intensity. Electron diffraction indicated ∼1° rotation about the [
] axis between the mesa and trench material, which was also observed in the image contrast of these two regions with g=
. Additionally, LCE samples prepared in [
] and [
] cross sections were used for comparing the growth rates in these two perpendicular directions. As theoretically expected,
growth in the [
] direction appears to proceed considerably faster than that in the [% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn%
hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9qqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x%
fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaaGymaiaaig% daceaIYaGbaebacaaIWaaaaa!38D1!\[11\bar 20\]] direction. 相似文献
17.
Organometallic vapor phase epitaxial growth of GaAs on 320 nm high mesas was used to study the dependence of lateral growth
upon the substrate misorientation from (100) and the mesa wall orientation on the substrate. GaAs (100) substrates were misoriented
by 3° toward eight major crystallographic directions, consisting of the four nearest [111] and [110] directions. The mesa
sidewalls were oriented either parallel to the 〈011〉 and 〈01
〉 directions or rotated by 45° to be parallel to the 〈001〉 and 〈010〉 directions. GaAs films were grown with TMGa and TBA at
T=575°C. The lateral growth rates were up to 25 times higher than the vertical growth rate of 1.3 μm/hour. Optical microscopy
and atomic force microscopy (AFM) showed that under the given growth conditions lateral growth off mesa sidewalls is most
rapid in the 〈011〉 and/or 〈0
〉 directions and less in the perpendicular 〈01
〉 and 〈0
1〉 directions (lateral growth anisotropy). By raising the temperature to 625°C lateral growth in the 〈01
〉 -〈0
1〉 directions increased while it remained almost constant in the 〈011〉 -〈0
〉 directions. Published results show that the partial pressure of As also affects lateral growth. Differences in the lateral
growth rates in the 〈011〉 and its opposite 〈0
〉 directions result from substrate misorientation but not from the orientation of the mesa walls on the substrate. Anisotropic
lateral growth rates in different crystallographic directions appear to be caused by both, (1) 1-dimensional Ga diffusion
defined by surface reconstruction, and (2) a relatively low energy barrier to atoms flowing over high-to-low terrace steps.
A lateral growth model is proposed that describes anisotropic lateral growth at mesa sidewalls in terms of growth conditions
and substrate misorientations. The model also explains the difference in the preferential lateral growth directions between
MBE and OMVPE. 相似文献
18.
To investigate the potential benefits of compositional grading for dislocation control in CdTe/Si growth, Cd1−xZnxTe buffer layers with x graded smoothly from 1 to 0 have been deposited on Si (211) surfaces. Growth has been characterized
using reflection high-energy electron diffraction (RHEED), x-ray diffraction (XRD), and etch pit density measurements. XRD
showed an increase in rocking curve full-width at half-maximum (FWHM) and global lattice tilt with decreasing x values. Tilt
was also observed to increase as buffer growth temperature was increased. Final surface dislocation densities did not decrease
below 7×106 cm−2. EPD surface dislocation measurements showed reduced dislocation densities and dislocation clustering along the
and
lines for CdTe cap layers grown on partially graded Cd1−xZnxTe buffer layers with slow compositional grading rates. Samples grown with faster grading rates showed higher final EPD values,
with dislocations clustering along the
and
lines. 相似文献
19.
The bias-enhanced nucleation (BEN) technique in hot-filament chemical vapor deposition (HF-CVD) has been applied to single
crystalline 6H-SiC substrates for the deposition of oriented diamond. The results of scanning electron microscopy (SEM) showed
that on (000
) face not only oriented diamond with relationship (111) Dia.//(000
)6H-SiC and 〈110〉Dia.//(11
0)6H-SiC, but also high nucleation density (>109 cm−2) have been achieved. In the case of deposition on (0001) face of 6H-SiC under the same experimental conditions, although
the nucleation density of diamond was enhanced, however, oriented diamond was not found. Diamond nucleation density is higher
on (0001) face than that on (000
) face. The differences in diamond oriented nucleation and nucleation density on these two faces are attributed to the difference
of their specific free surface energy. The experimental results have shown that the 6H-SiC substrate surfaces are etched by
the accelerated H-ions during BEN process, and many micro-triangular crystals with the faces of the kind {01
4} are formed on the substrate surface. Diamonds nucleate on the top of the micro-triangular crystals. Micro-Raman spectrum
shows a strong feature of diamond crystals at 1334 cm−1. 相似文献
20.
Roskowski A. M. Preble E. A. Einfeldt S. Miraglia P. M. Davis R. F. 《Journal of Electronic Materials》2002,31(5):421-428
High-resolution x-ray diffraction (XRD) and atomic force microscopy (AFM) of pendeo-epitaxial (PE) GaN films confirmed transmission
electron microscopy (TEM) results regarding the reduction in dislocations in the wings. Wing tilt ≤0.15° was due to tensile
stresses in the stripes induced by thermal expansion mismatch between the GaN and the SiC substrate. A strong D°X peak at
≈3.466 eV (full-width half-maximum (FWHM) ≤300 μeV) was measured in the wing material. Films grown at 1020°C exhibited similar
vertical [0001] and lateral [11
0] growth rates. Increasing the temperature increased the latter due to the higher thermal stability of the GaN(11
0). The (11
0) surface was atomically smooth under all growth conditions with a root mean square (RMS)=0.17 nm. 相似文献