共查询到19条相似文献,搜索用时 171 毫秒
1.
Effect of F doping on capacitance-voltage characteristics of SiCOH low-k films metal-insulator-semiconductor 下载免费PDF全文
This paper investigates the capacitance-voltage(C-V) characteristics of F doping SiCOH low dielectric constant films metal-insulator-semiconductor structure.The F doping SiCOH films are deposited by decamethylcyclopentasiloxane(DMCPS) and trifluromethane(CHF3) electron cyclotron resonance plasmas.With the CHF3/DMCPS flow rate ratio from 0 to 0.52,the positive excursion of C-V curves and the increase of flat-band voltage VFB from 6.1 V to 32.2 V are obtained.The excursion of C-V curves and the shift of VFB are related to the change of defects density and type at the Si/SiCOH interface due to the decrease of Si and O concentrations,and the increase of F concentration.At the CHF3/DMCPS flow rate ratio is 0.12,the compensation of F-bonding dangling bond to Si dangling bond leads to a small VFB of 2.0 V. 相似文献
2.
A specially designed experiment is performed for investigating gate-induced
drain leakage (GIDL) current in 90nm CMOS technology using lightly-doped
drain (LDD) NMOSFET. This paper shows that the drain bias $V_{\rm D}$ has a
strong effect on GIDL current as compared with the gate bias $V_{\rm G}$ at the
same drain--gate voltage $V_{\rm DG}$. It is found that the difference between
$I_{\rm D}$ in the off-state $I_{\rm D}-V_{\rm G}$ characteristics and the
corresponding one in the off-state $I_{\rm D}-V_{\rm D}$ characteristics, which is
defined as $I_{\rm DIFF}$, versus $V_{\rm DG}$ shows a peak. The difference between
the influences of $V_{\rm D}$ and $V_{\rm G}$ on GIDL current is shown
quantitatively by $I_{\rm DIFF}$, especially in 90nm scale. The difference is
due to different hole tunnellings. Furthermore, the maximum $I_{\rm DIFF
}$($I_{\rm DIFF,MAX})$ varies linearly with $V_{\rm DG}$ in logarithmic coordinates
and also $V_{\rm DG}$ at $I_{\rm DIFF,MAX}$ with $V_{\rm F}$ which is the characteristic
voltage of $I_{\rm DIFF}$. The relations are studied and some related
expressions are given. 相似文献
3.
Effect of F- and CH-Doped on Dielectric Properties of SiCOH Films Deposited by Decamethylcyclopentasiloxane Electron Cyclotron Resonance Plasma 下载免费PDF全文
We investigate the effect of CH-doped and F-doped on dielectric properties of SiCOH films deposited by de- camethylcyclopentasiloxane (DMCPS) electron cyclotron resonance plasma. The dielectric constant k is closely related to the configurations of films. For the films deposited only using DMCPS, the minimum k is as low as 2.88. By adding CH4 in the precursor, the k value can be reduced to 2.45 due to the film density decreasing by incorporating large size CHx groups. By adding CHF3 in the precursor, the k value can also be reduced to 2.48 due to the incorporation of the weak-polarization F atom. Thus the dielectric constant for SiCOH films depends on not only the film density but also the polarization of atoms. By increasing the film density or by reducing the polarization of atoms under the condition of a lower film density, the low dielectric constant SiCOH films can be obtained. 相似文献
4.
improvement of electrical properties of Cu/SiCOH low-k film integrated system by O2 plasma treatment 下载免费PDF全文
This paper investigates the effect of O2 plasma treatment on the electric property of Cu/SiCOH low dielectric constant (low-k) film integrated structure. The results show that the leakage current of Cu/SiCOH low-k integrated structure can be reduced obviously at the expense of a slight increase in dielectric constant k of SiCOH films. Bythe Fourier transform infrared (FTIR) analysis on the bonding configurations of SiCOH films treated by O2 plasmar it is found that the decrease of leakage current is related to the increase of Si-O cages originating from the linkage of Si dangling bonds through O, which makes the open pores sealed and reduces the diffusion of Cu to pores. 相似文献
5.
Mass Spectrometry Investigation on Decamethylcyclopentasiloxane Electron Cyclotron Resonance Plasma for SiCOH Film Deposition 下载免费PDF全文
We investigate the fragmentation behaviour of decamethylcyclopentasiloxane (DMCPS) plasma using a quadrupole mass spectrometry, which is used as the precursor to deposit SiCOH film in an electron cyclotron resonance (ECR) plasma system. The structure of DMCPS molecules comprises a fivefold Si-O ring and ten -CH3 groups bonded at five Si atoms. In ECR discharge plasma, the main fragmentation behaviour of DMCPS includes two stages. One is the breaking of fivefold Si-O rings and then the formation of threefold Si-O rings and Si-O chain species. The other is the decomposing of hydrocarbon groups from Si atoms and then the crosslink of hydrocarbon species. Combined with the bonding configuration of SiCOH films, the relation between species in ECR plasma and films structures is analysed. 相似文献
6.
Study on spectroscopic parameters and molecular constants of HCl(X~1Σ~+) molecule by using multireference configuration interaction approach 下载免费PDF全文
Equilibrium internuclear separations, harmonic frequencies
and potential energy curves (PECs) of HCl($X^{1}\Sigma ^{ + })$
molecule are investigated by using the highly accurate valence
internally contracted multireference configuration interaction
(MRCI) approach in combination with a series of
correlation-consistent basis sets in the valence range. The PECs are
all fitted to the Murrell--Sorbie function, and they are used to
accurately derive the spectroscopic parameters ($D_{\rm e}$,
$D_{0}$, $\omega_{\rm e}\chi_{\rm e}$, $\alpha_{\rm e}$ and $B_{\rm
e})$. Compared with the available measurements, the PEC obtained at
the basis set, aug-cc-pV5Z, is selected to investigate the
vibrational manifolds. The constants $D_{0}$, $D_{\rm e}$, $R_{\rm
e}$, $\omega_{\rm e}$, $\omega_{\rm e}\chi_{\rm e}$, $\alpha_{\rm
e}$ and $B_{\rm e}$ at this basis set are 4.4006~eV, 4.5845~eV,
0.12757~nm, 2993.33~cm$^{ - 1}$, 52.6273~cm$^{ - 1}$, 0.2981~cm$^{ -
1}$ and 10.5841~cm$^{ - 1}$, respectively, which almost perfectly
conform to the available experimental results. With the potential
determined at the MRCI/aug-cc-pV5Z level of theory, by numerically
solving the radial Schr\"{o}dinger equation of nuclear motion in the
adiabatic approximation, a total of 21 vibrational levels are
predicted. Complete vibrational levels, classical turning points,
inertial rotation and centrifugal distortion constants are
reproduced, which are in excellent agreement with the available
Rydberg--Klein--Rees data. Most of these theoretical vibrational
manifolds are reported for the first time to the best of our
knowledge. 相似文献
7.
In the framework of density functional theory, using the plane-wave
pseudopotential method, the nitrogen vacancy ($V_{\rm N})$ in both
wurtzite and zinc-blende AlN is studied by the supercell approach.
The atom configuration, density of states, and formation energies of
various charge states are calculated. Two defect states are
introduced by the defect, which are a doubly occupied single state
above the valance band maximum (VBM) and a singly occupied triple
state below the conduction band minimum (CBM) for wurtzite AlN and
above the CBM for zinc-blende AlN. So $V_{\rm N}$ acts as a deep
donor in wurtzite AlN and a shallow donor in zinc-blende AlN. A
thermodynamic transition level $E({3 + } \mathord{\left/ {\vphantom
{{3 + } + }} \right. \kern-\nulldelimiterspace} + )$ with very low
formation energy appears at 0.7 and 0.6eV above the VBM in wurtzite
and zinc-blende structure respectively, which may have a wide shift
to the low energy side if atoms surrounding the defect are not fully
relaxed. Several other transition levels appear in the upper part of
the bandgap. The number of these levels decreases with the structure
relaxation. However, these levels are unimportant to AlN properties
because of their high formation energy. 相似文献
8.
Effect of substrate temperature on the growth and properties of boron-doped microcrystalline silicon films 下载免费PDF全文
Highly conductive boron-doped hydrogenated microcrystalline silicon (\mu
c-Si:H) films are prepared by very high frequency plasma enhanced chemical
vapour deposition (VHF PECVD) at the substrate temperatures $T_{\rm S})$
ranging
from 90$^\circ$C to 270$^\circ$C. The effects of $T_{\rm S}$ on the growth and
properties of the films are investigated. Results indicate that the growth
rate, the electrical (dark conductivity, carrier concentration and Hall
mobility) and structural (crystallinity and grain size) properties are all
strongly dependent on $T_{\rm S}$. As $T_{\rm S}$ increases, it is
observed that 1)
the growth rate initially increases and then arrives at a maximum value of
13.3 nm/min at $T_{\rm S}$=210$^\circ$C, 2) the crystalline volume fraction
($X_{\rm c})$ and the grain size increase initially, then reach their maximum
values at $T_{\rm S}$=140$^\circ$C, and finally decrease, 3) the dark
conductivity ($\sigma _{\rm d})$, carrier concentration and Hall mobility have
a similar dependence on $T_{\rm S}$ and arrive at their maximum values at
$T_{\rm S}$=190$^\circ$C. In addition, it is also observed that at a lower
substrate temperature $T_{\rm S}$, a higher dopant concentration is required in
order to obtain a maximum $\sigma _{\rm d}$. 相似文献
9.
Investigations on spectroscopic parameters, vibrational levels, classical turning points and inertial rotation and centrifugal distortion constants for the X1∑+g state of sodium dimer 下载免费PDF全文
The density functional theory (B3LYP, B3P86) and the quadratic
configuration-interaction method including single and double
substitutions (QCISD(T), QCISD) presented in Gaussian03 program
package are employed to calculate the equilibrium internuclear
distance $R_{\rm e}$, the dissociation energy $D_{\rm e }$ and the
harmonic frequency $\omega _{\rm e}$ for the $X{}^{1}\Sigma^{ +
}_{\rm g}$ state of sodium dimer in a number of basis sets. The
conclusion is gained that the best $R_{\rm e}$, $D_{\rm e}$ and
$\omega _{\rm e}$ results can be attained at the
QCISD/6-311G(3df,3pd) level of theory. The potential energy curve at
this level of theory for this state is obtained over a wide
internuclear separation range from 0.16 to 2.0~nm and is fitted to
the analytic Murrell--Sorbie function. The spectroscopic parameters
$D_{\rm e}$, $D_{0}$, $R_{\rm e}$, $\omega _{\rm e}$,
$\omega _{\rm e}\chi _{\rm e}$,
$\alpha _{\rm e}$
and $B_{\rm e}$ are calculated to be 0.7219~eV,
0.7135~eV, 0.31813~nm, 151.63~cm$^{ - 1}$, 0.7288~cm$^{ - 1}$,
0.000729~cm$^{ - 1}$ and 0.1449~cm$^{ - 1}$, respectively, which are in good
agreement with the measurements. With the potential obtained at the
QCISD/6-311G(3df,3pd) level of theory, a total of 63 vibrational
states is found when $J=0$ by solving the radial Schr\"{o}dinger equation
of nuclear motion. The vibrational level, corresponding classical turning
point and inertial rotation constant are computed for each vibrational
state. The centrifugal distortion constants
($D_{\upsilon }\, H_{\upsilon }$,
$L_{\upsilon }$, $M_{\upsilon }$, $N_{\upsilon }$ and $O_{\upsilon })$ are
reported for the first time for the first 31 vibrational states when $J=0$. 相似文献
10.
Electronic structure and defect states of transition films from amorphous to microcrystalline silicon studied by surface photovoltage spectroscopy 下载免费PDF全文
In this paper, surface photovoltage spectroscopy (SPS) is used to
determine the electronic structure of the hydrogenated transition Si
films. All samples are prepared by using helicon wave plasma-enhanced
chemical vapour deposition technique, the films exhibit a transition
from the amorphous phase to the microcrystalline phase with
increasing temperature. The film deposited at lower substrate
temperature has the amorphous-like electronic structure with two
types of dominant defect states corresponding to the occupied Si
dangling bond states (D0/D- and the empty Si dangling
states (D+). At higher substrate temperature, the
crystallinity of the deposited films increases, while their band gap
energy decreases. Meanwhile, two types of additional defect states is
incorporate into the films as compared with the amorphous
counterpart, which is attributed to the interface defect states
between the microcrystalline Si grains and the amorphous matrix. The
relative SPS intensity of these two kinds of defect states in samples
deposited above 300\du increases first and decreases afterwards,
which may be interpreted as a result of the competition between
hydrogen release and crystalline grain size increment with increasing
substrate temperature. 相似文献
11.
The defects associated with lead vacancies(VPd)in lead tungstate crystals(PbWO4) are investigated by the relativistic self-consistent discrete variational embedded cluster method.We focus on the density of states and the effect of Vpb on surroundings,the results show that the existence of Vpb can diminish the bandwidth of WOr^2- group,however,it can neither produce O^- and Pb^3 ions nor result in absorptions at 350 and 420nm,The charge balance of VPb may be evenly compensated by the surrounding oxygen ions. 相似文献
12.
The Ni/4H-SiC Schottky barrier diodes (SBDs) and transfer length
method (TLM) test patterns of Ni/4H-SiC Ohmic contacts were
fabricated, and irradiated with 1~MeV electrons up to a dose of
3.43× 1014~e/cm-2. After radiation, the forward
currents of the SBDs at 2~V decreased by about 50%, and the
reverse currents at -200~V increased by less than 30%. Schottky
barrier height (φ B ) of the Ni/4H-SiC SBD increased
from 1.20~eV to 1.21~eV under 0~V irradiation bias, and decreased
from 1.25~eV to 1.19~eV under -30~V irradiation bias. The
degradation of φ B could be explained by the variation
of interface states of Schottky contacts. The on-state resistance
(Rs) and the reverse current increased with the dose, which
can be ascribed to the radiation defects in bulk material. The
specific contact resistance (\rhoc) of the Ni/SiC Ohmic
contact increased from 5.11× 105~Ωega.cm2 to 2.97× 10-4~Ωega.cm2. 相似文献
13.
This paper reports that single-layer and graded Au-TiO2 granular composite films with Au atom content 15%- 66% were prepared by using reactive co-sputtering technique. The third-order optical nonlinearity of single-layer and graded composite films was investigated by using s- and p-polarized Z-scans in femtosecond time scale. The nonlinear absorption coefficient βeff of single-layer Au-TiO2 films is measured to be -2.3×10^3-0.76×10^3 cm/GW with Au atom content 15%-66%. The βeff value of the 10-layer Au-TiO2 graded film is enhanced to be -2.1×10^4cm/GW calculated from p-polarized Z-scans, which is about ten times the maximum βeff of single-layer films. Broadened response in the wavelength region 730-860 nm of the enhanced optical nonlinearity of graded Au-TiO2 composite films was also investigated. 相似文献
14.
Based on the beyond-mean-field Skyrme–Hartree–Fock model, impurity effects of the Λhyperon in the hypernuclear systems ${}_{\,{\rm{\Lambda }}}^{25}$ Mg and ${}_{\,{\rm{\Lambda }}}^{29}$ Si are investigated, respectively. Four cases, in which the Λhyperon occupies the single-particle orbitals ${\rm{\Lambda }}$[000]${\tfrac{1}{2}}^{+}$, ${\rm{\Lambda }}$[110]${\tfrac{1}{2}}^{-}$, ${\rm{\Lambda }}$[101]${\tfrac{3}{2}}^{-}$ and ${\rm{\Lambda }}$[101]${\tfrac{1}{2}}^{-}$, are focused. In each case, the potential energy surface and the energy curves projected on certain angular momenta are employed to show the influence of the Λhyperon on the nuclear core. Beside the shrinkage effect that is induced by the Λhyperon occupying the sΛ orbital, it is found that the Λhyperon on the pΛ orbital, ${\rm{\Lambda }}$[110]${\tfrac{1}{2}}^{-}$, drives the nuclear core toward a prolate shape, while the ones on the other two pΛ orbitals, ${\rm{\Lambda }}$[101]${\tfrac{3}{2}}^{-}$ and ${\rm{\Lambda }}$[101]${\tfrac{1}{2}}^{-}$, drive the nuclear core toward an oblate shape. The energy spectra and the corresponding intra-band E2 transition rates for the rotational bands are given as a prediction for future experiments. 相似文献
15.
This paper reports that a novel type of suspended ZnO nanowire field-effect
transistors (FETs) were successfully fabricated using a
photolithography process, and their electrical properties were
characterized by I--V measurements. Single-crystalline ZnO
nanowires were synthesized by a hydrothermal method, they were used
as a suspended ZnO nanowire channel of back-gate field-effect
transistors (FET). The fabricated suspended nanowire FETs showed a
p-channel depletion mode, exhibited high on--off current ratio of
~105. When VDS=2.5 V, the peak transconductances
of the suspended FETs were 0.396 μS, the oxide capacitance was
found to be 1.547 fF, the pinch-off voltage VTH was about
0.6 V, the electron mobility was on average 50.17 cm2/Vs. The
resistivity of the ZnO nanowire channel was estimated to be
0.96× 102Ω cm at VGS = 0 V. These
characteristics revealed that the suspended nanowire FET fabricated
by the photolithography process had excellent performance. Better
contacts between the ZnO nanowire and metal electrodes could be
improved through annealing and metal deposition using a focused ion
beam. 相似文献
16.
Novel material for nonvolatile ovonic unified memory (OUM)-Ag11In12Te26Sb51 phase change semiconductor 下载免费PDF全文
In this paper, Ag_{11}In_{12}Te_{26}Sb_{51} phase change semiconductor films have been prepared by dc sputtering. The crystallization behaviour of amorphous Ag_{11}In_{12}Te_{26}Sb_{51} thin films was investigated by using differential scanning calorimetry and x-ray diffraction. It was found that the crystallization temperature is about 483K and the melting temperature is 754.8K and the activation energy for crystallization, E_a, is 2.07eV. The crystalline Ag_{11}In_{12}Te_{26}Sb_{51} films were obtained using initializer. The initialization conditions have a great effect on the sheet resistance of Ag_{11}In_{12}Te_{26}Sb_{51} films. We found that the effect of the initialization condition on the sheet resistance can be ascribed to the crystallinity of Ag_{11}In_{12}Te_{26}Sb_{51} films. The sheet resistance of the amorphous (R_{amo}) film is found to be larger than 1×10^6Ω and that of the crystalline (R_{cry}) film lies in the range from about 10^3 to 10^4Ω. So we have the ratio R_{amo}/R_{cry}=10^2~10^3, which is sufficiently large for application in memory devices. 相似文献
17.
A first-principles study of the catalytic mechanism of the dehydriding reaction of LiNH2 through adding Ti catalysts 下载免费PDF全文
Experiments on a ball milled mixture with a 1:1 molar ratio of LiNH2 and LiH with a small amount(1 mol %) of Ti nano,TiCl3 and TiO nano 2 have revealed a superior catalytic effect on Li-N-H hydrogen storage materials.In the x-ray diffraction profiles,no trace of Ti nano,TiCl3 and TiO nano 2 was found in these doped composites,by which we deduced that Ti atoms enter LiNH2 by partial element substitution.A first-principles plane-wave pseudopotential method based on density functional theory has been used to investigate the catalytic effects of Ti catalysts on the dehydrogenating properties of LiNH2 system.The results show that Ti substitution can reduce the dehydrogenation reaction activation energy of LiNH2 and improve the dehydrogenating properties of LiNH2.Based on the analysis of the density of states and overlap populations for LiNH2 before and after Ti substitution,it was found that the stability of the system of LiNH2 is reduced,which originates from the increase of the valence electrons at the Fermi level(EF) and the decrease of the highest occupied molecular orbital(HOMO)-lowest unoccupied molecular orbital(LUMO) gap(△EH-L) near E F.The catalytic effect of Ti on the dehydrogenating kinetics of LiNH2 may be attributed to the reduction of average populations between N-H per unit bond length(nm-1),which leads to the reduction of the chemical bond strength of N-H. 相似文献
18.
In this paper the generation of four-wave mixing (FWM) signal using a
noncycling transition of caesium atoms is investigated when the pumping laser
is locked to the transition $6{\rm S}_{1/2}F=4\to6{\rm P}_{3/2}F'=4$, and
meanwhile the probe frequency is scanned across the $6{\rm S}_{1/2}F=4
\to6{\rm P}_{3/2}$ transition. The efficiency of the four-wave mixing signal
as a function of the intensity of the pumping beams and the detuning of the
pumping beams is also studied. In order to increase the detection
efficiency, a repumping laser which is resonant with $6{\rm S}_{1/2}
F=3\to 6{\rm P}_{3/2}F'=4$ transition is used. A theoretical model is also
introduced, and the theoretical results are in qualitative agreement with
experimental ones. 相似文献
19.
A novel Si-rich SiN bilayer passivation with thin-barrier AlGaN/GaN HEMTs for high performance millimeter-wave applications 下载免费PDF全文
Zhihong Chen 《中国物理 B》2022,31(11):117105-117105
We demonstrate a novel Si-rich SiN bilayer passivation technology for AlGaN/GaN high electron mobility transistors (HEMTs) with thin-barrier to minimize surface leakage current to enhance the breakdown voltage. The bilayer SiN with 20-nm Si-rich SiN and 100-nm Si$_{3}$N$_{4}$ was deposited by plasma-enhanced chemical vapor deposition (PECVD) after removing 20-nm SiO$_{2}$ pre-deposition layer. Compared to traditional Si$_{3}$N$_{4}$ passivation for thin-barrier AlGaN/GaN HEMTs, Si-rich SiN bilayer passivation can suppress the current collapse ratio from 18.54% to 8.40%. However, Si-rich bilayer passivation leads to a severer surface leakage current, so that it has a low breakdown voltage. The 20-nm SiO$_{2}$ pre-deposition layer can protect the surface of HEMTs in fabrication process and decrease Ga-O bonds, resulting in a lower surface leakage current. In contrast to passivating Si-rich SiN directly, devices with the novel Si-rich SiN bilayer passivation increase the breakdown voltage from 29 V to 85 V. Radio frequency (RF) small-signal characteristics show that HEMTs with the novel bilayer SiN passivation leads to $f_{\rm T}/f_{\rm max}$ of 68 GHz/102 GHz. At 30 GHz and $V_{\rm DS} = 20$ V, devices achieve a maximum $P_{\rm out}$ of 5.2 W/mm and a peak power-added efficiency (PAE) of 42.2%. These results indicate that HEMTs with the novel bilayer SiN passivation can have potential applications in the millimeter-wave range. 相似文献