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1.
Hot carriers injection (HCI) tests for ultra-short channel n-MOSFET
devices were studied. The experimental data of short channel devices
(75--90\,nm), which does not fit formal degradation power law well,
will bring severe error in lifetime prediction. This phenomenon
usually happens under high drain voltage ($V_{\rm d}$) stress
condition. A new model was presented to fit the degradation curve
better. It was observed that the peak of the substrate current under
low drain voltage stress cannot be found in ultra-short channel
device. Devices with different channel lengths were studied under
different $V_{\rm d}$ stresses in order to understand the relations
between peak of substrate current ($I_{\rm sub}$) and channel
length/stress voltage. 相似文献
2.
Effect of STI-induced mechanical stress on leakage current in deep submicron CMOS devices 总被引:1,自引:0,他引:1
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The shallow trench isolation (STI) induced mechanical stress
significantly affects the CMOS device off-state leakage behaviour. In
this paper, we designed two types of devices to investigate this
effect, and all leakage components, including sub-threshold leakage
($I_{\rm sub})$, gate-induced-drain-leakage ($I_{\rm GIDL})$, gate
edge-direct-tunnelling leakage ($I_{\rm EDT})$ and
band-to-band-tunnelling leakage ($I_{\rm BTBT})$ were analysed. For
NMOS, $I_{\rm sub}$ can be reduced due to the mechanical stress
induced higher boron concentration in well region. However, the GIDL
component increases simultaneously as a result of the high well
concentration induced drain-to-well depletion layer narrowing as well
as the shrinkage of the energy gap. For PMOS, the only mechanical
stress effect on leakage current is the energy gap narrowing induced
GIDL increase. 相似文献
3.
A 4H-SiC trench MOSFET structure with wrap N-type pillar for low oxide field and enhanced switching performance
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An optimized silicon carbide (SiC) trench metal-oxide-semiconductor field-effect transistor (MOSFET) structure with side-wall p-type pillar (p-pillar) and wrap n-type pillar (n-pillar) in the n-drain was investigated by utilizing Silvaco TCAD simulations. The optimized structure mainly includes a p$+$ buried region, a light n-type current spreading layer (CSL), a p-type pillar region, and a wrapping n-type pillar region at the right and bottom of the p-pillar. The improved structure is named as SNPPT-MOS. The side-wall p-pillar region could better relieve the high electric field around the p$+$ shielding region and the gate oxide in the off-state mode. The wrapping n-pillar region and CSL can also effectively reduce the specific on-resistance ($R_{\rm on,sp}$). As a result, the SNPPT-MOS structure exhibits that the figure of merit (FoM) related to the breakdown voltage ($V_{\rm BR}$) and $R_{\rm on,sp}$ ($V_{\rm BR}^{2}R_{\rm on,sp}$) of the SNPPT-MOS is improved by 44.5%, in comparison to that of the conventional trench gate SJ MOSFET (full-SJ-MOS). In addition, the SNPPT-MOS structure achieves a much faster-witching speed than the full-SJ-MOS, and the result indicates an appreciable reduction in the switching energy loss. 相似文献
4.
This paper studies an oxide/silicon core/shell nanowire MOSFET(OS-CSNM).Through three-dimensional device simulations,we have demonstrated that the OS-CSNM has a lower leakage current and higher I on /I off ratio after introducing the oxide core into a traditional nanowire MOSFET(TNM).The oxide/silicon OS-CSNM structure suppresses threshold voltage roll-off,drain induced barrier lowering and subthreshold swing degradation.Smaller intrinsic device delay is also observed in OS-CSNM in comparison with that of TNM. 相似文献
5.
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
6.
We fabricated a set of symmetric gate-recess devices with gate length of 70 nm.We kept the source-to-drain spacing(LSD)unchanged,and obtained a group of devices with gate-recess length(Lrecess)from 0.4μm to 0.8μm through process improvement.In order to suppress the influence of the kink effect,we have done SiNX passivation treatment.The maximum saturation current density(IDmax)and maximum transconductance(gm,max)increase as Lrecess decreases to 0.4μm.At this time,the device shows IDmax=749.6 mA/mm at VGS=0.2 V,VDS=1.5 V,and gm,max=1111 mS/mm at VGS=?0.35 V,VDS=1.5 V.Meanwhile,as Lrecess increases,it causes parasitic capacitance Cgd and gd to decrease,making fmax drastically increases.When Lrecess=0.8μm,the device shows fT=188 GHz and fmax=1112 GHz. 相似文献
7.
The role of hydrogen in hydrogenated microcrystalline silicon film and in deposition process with VHF-PECVD technique
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The role of hydrogen in hydrogenated microcrystalline silicon ($\mu $c-Si:H)
thin films in deposition processes with very high frequency
plasma-enhanced chemical vapour deposition (VHF-PECVD) technique have been
investigated in this paper. With \textit{in situ} optical emission spectroscopy (OES)
diagnosis during the fabrication of $\mu $c-Si:H thin films under different
plasma excitation frequency $\nu _{\rm e }$ (60MHz--90MHz), the
characteristic peak intensities ($I_{{\rm SiH}^*}$, $I_{{\rm H}\alpha^*}$
and $I_{{\rm H}\beta ^*}$) in SiHVHF-PECVD技术 氢化微晶硅 光发射光谱 薄膜学 VHF-PECVD technique, hydrogenated microcrystalline silicon, role of hydrogen, optical emission spectroscopy Project supported by the Natural Science Foundation of Guangdong
Province, China (Grant No 05300378), the State Key Development Program for Basic Research
of China (Grant Nos G2000028202 and G2000028203) and the Program on Natural
Science of Jinan University, Guangzhou, China (Grant No 51204056). 2005-11-25 2005-11-252006-01-05 The role of hydrogen in hydrogenated microcrystalline silicon (μc-Si:H) thin films in deposition processes with very high frequency plasma-enhanced chemical vapour deposition (VHF-PECVD) technique have been investigated in this paper. With in situ optical emission spectroscopy (OES) diagnosis during the fabrication of μc-Si:H thin films under different plasma excitation frequency Ve (60MHz-90MHz), the characteristic peak intensities (IsiH*, IHα* and IHβ* ) in SiH4+H2 plasma and the ratio of (IHα* + IHβ* ) to IsiH* were measured; all the characteristic peak intensities and the ratio (IHα* + IHβ* )/IsiH* are increased with plasma excitation frequency. It is identified that high plasma excitation frequency is favourable to promote the decomposition of SiH4+H2 to produce atomic hydrogen and SiHx radicals. The influences of atomic hydrogen on structural properties and that of SiHx radicals on deposition rate of μc-Si:H thin films have been studied through Raman spectra and thickness measurements, respectively. It can be concluded that both the crystalline volume fraction and deposition rate are enhanced with the increase of plasma excitation frequency, which is in good accord with the OES results. By means of FTIR measurements, hydrogen contents of μc-Si:H thin films deposited at different plasma excitation frequency have been evaluated from the integrated intensity of wagging mode near 640 cm^-1. The hydrogen contents vary from 4% to 5%, which are much lower than those of μc-Si:H films deposited with RF-PECVD technique. This implies that μc-Si:H thin films deposited with VHF-PECVD technique usually have good stability under light-soaking. 相似文献
8.
Effect of F doping on capacitance-voltage characteristics of SiCOH low-k films metal-insulator-semiconductor structure
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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 (CHF7755, 6855 http://cpb.iphy.ac.cn/CN/10.1088/1674-1056/19/5/057701 https://cpb.iphy.ac.cn/CN/article/downloadArticleFile.do?attachType=PDF&id=111779 F-SiCOH, low-k dielectrics, capacitance--voltage
characteristic Project supported by the National
Natural Science Foundation of China (Grant No.~10575074). 2/4/2009 12:00:00 AM 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 (CHF$_{3})$ electron cyclotron resonance plasmas.
With the CHF$_{3}$/DMCPS flow rate ratio from 0 to 0.52, the
positive excursion of $C$--$V$ curves and the increase of flat-band
voltage $V_{\rm FB}$ from $-6.1$~V to 32.2~V are obtained. The
excursion of $C$--$V$ curves and the shift of $V_{\rm FB}$ 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 CHF$_{3}$/DMCPS flow rate ratio
is 0.12, the compensation of F-bonding dangling bond to Si dangling
bond leads to a small $V_{\rm FB}$ of 2.0~V. 半导体结构;电压特性;电容电压;绝缘体;薄膜;金属;电子回旋共振等离子体;兴奋剂 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 decamethylcyclopentasilox-ane [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 fiat-band voltage VFB from -6.1 V to 32.2V 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 2.0V. 相似文献
9.
An investigation of ionization and displacement damage in
silicon NPN bipolar junction transistors (BJTs) is presented. The
transistors were irradiated separately with 90-keV electrons, 3-MeV
protons and 40-MeV Br ions. Key parameters were measured {\em
in-situ} and the change in current gain of the NPN BJTS was obtained
at a fixed collector current (I_{\rm c}=1~mA). To characterise the
radiation damage of NPN BJTs, the ionizing dose D_{\i} and
displacement dose D_{\d} as functions of chip depth in the NPN
BJTs were calculated using the SRIM and Geant4 code for protons,
electrons and Br ions, respectively. Based on the discussion of the
radiation damage equation for current gain, it is clear that the
current gain degradation of the NPN BJTs is sensitive to both
ionization and displacement damage. The degradation mechanism of
the current gain is related to the ratio of D_{\rm d}/(D_{\rm
d}+D_{\rm i}) in the sensitive region given by charged particles.
The irradiation particles leading to lower D_{\rm d}/(D_{\rm
d}+D_{\rm i}) within the same chip depth at a given total dose
would mainly produce ionization damage to the NPN BJTs. On the other
hand, the charged particles causing larger D_{\rm d}/(D_{\rm
d}+D_{\rm i}) at a given total dose would tend to generate
displacement damage to the NPN BJTs. The Messenger--Spratt equation
could be used to describe the experimental data for the latter
case. 相似文献
10.
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
11.
This article investigates an improved 4H-SiC trench gate metal-oxide-semiconductor field-effect transistor (MOSFET) (UMOSFET) fitted with a super-junction (SJ) shielded region. The modified structure is composed of two n-type conductive pillars, three p-type conductive pillars, an oxide trench under the gate, and a light n-type current spreading layer (NCSL) under the p-body. The n-type conductive pillars and the light n-type current spreading layer provide two paths to and promote the diffusion of a transverse current in the epitaxial layer, thus improving the specific on-resistance ($R_{\rm on,sp}$). There are three p-type pillars in the modified structure, with the p-type pillars on both sides playing the same role. The p-type conductive pillars relieve the electric field ($E$-field) in the corner of the trench bottom. Two-dimensional simulation (silvaco TCAD) indicates that $R_{\rm on,sp }$ of the modified structure, and breakdown voltage ($V_{\rm BR}$) are improved by 22.2% and 21.1% respectively, while the maximum figure of merit (${\rm FOM}=V^{2}_{\rm BR}/R_{\rm on,sp}$) is improved by 79.0%. Furthermore, the improved structure achieves a light smaller low gate-to-drain charge ($Q_{\rm gd}$) and when compared with the conventional UMOSFET (conventional-UMOS), it displays great advantages for reducing the switching energy loss. These advantages are due to the fact that the p-type conductive pillars and n-type conductive pillars configured under the gate provide a substantial charge balance, which also enables the charge carriers to be extracted quickly. In the end, under the condition of the same total charge quantity, the simulation comparison of gate charge and OFF-state characteristics between Gauss-doped structure and uniform-doped structure shows that Gauss-doped structure increases the $V_{\rm BR}$ of the device without degradation of dynamic performance. 相似文献
12.
A novel Si-rich SiN bilayer passivation with thin-barrier AlGaN/GaN HEMTs for high performance millimeter-wave applications
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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
13.
This paper studies the properties of a kind of portable ultra-bright
microfocus x-ray source with the Monte-Carlo method in detail. The new
x-ray source consists of an electron-emission system, an
electrostatic focusing system and a metal target. A crystal
Lanthanum Hexaboride cathode, a Wehnelt grid and an extracted
electrode compose the triode electrode electron-gun system. Two
equal radius cylinder electrodes form the focusing system. The key
factors determining the focus properties of the electron beam such as the
ratio Dw/H, grid bias Vg, and the properties of the
extracted electrode are numerically studied. The calculated results
reveal that when Dw/H, Vg, the length of
the extracted electrode, and the distance between the grid and the extracted
electrode equals 5, --0.6~kV, 10~mm, and 8~mm respectively, the
electron beam focal spot can be concentrated down to 9~μm in
radius and a reasonable focal length about 72.5~mm can be achieved,
at the same time, the cathode emission currents can be as high as
30~mA. 相似文献
14.
The comparison between single-point energy scanning (SPES) and geometry optimization (OPT) in determining the equilibrium geometry of the α^3∑u^+ state for ^7Li2 is made at numerous basis sets such as 6-311++G(2df), cc-PVTZ, 6-311++G(2df, p), 6-311G(3df,3pd), 6-311++G(2df,2pd), D95(3df,3pd), 6-311++G, DGDZVP, 6-311++G(3df,2pd), 6-311G(2df,2pd), D95V++, CEP-121G, 6-311++G(d,p), 6-311++G(2df, pd) and 6-311++G(3df,3pd) in full active space using a symmetry-adapted-cluster/ symmetry-adapted-cluster configuration-interaction (SAC/SAC=CI) method presented in Gaussian03 program package. The difference of the equilibrium geometries obtained by SPES and by OPT is reported. Analyses show that the results obtained by SPES are more reasonable than those obtained by OPT. We have calculated the complete potential energy curves at those sets over a wide internuclear distance range from about 3.0α0 to 37.0α0, and the conclusion is that the basis set cc-PVTZ is the most suitable one. With the potential obtained at ccopVTZ, the spectroscopic data (Te, De, D0, ωe,ωeХe, αe and Be) are computed and they are 1.006 eV, 338.71 cm^-1, 307.12 cm^-1, 64.88 cm^-1, 3.41 cm^-1, 0.0187 cm^-1 and 0.279 cm^-1, respectively, which are in good agreement with recent measurements. The total 11 vibrational states are found at J=0. Their corresponding vibrational levels and classical turning points are computed and compared with available RKR data, and good agreement is found. One inertial rotation constant (By) and six centrifugal distortion constants (Dr Hv, Lv, My, Nv, and Ov) are calculated. The scattering length is calculated to be -27.138α0, which is in good accord with the experimental data. 相似文献
15.
Effect of substrate temperature on the growth and properties of boron-doped microcrystalline silicon films
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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
16.
Electron tunnelling phase time and dwell time through an associated delta potential barrier
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The electron tunnelling phase time τP and dwell time τD through an associated delta potential barrier U(x) = ξδ(x) are calculated and both are in the order of 10^-17~10^-16s. The results show that the dependence of the phase time on the delta barrier parameter ξ can be described by the characteristic length lc = h^2/meξ and the characteristic energy Ec=meξ^2/h^2 of the delta barrier, where me is the electron mass, lc and Ec are assumed to be the effective width and height of the delta barrier with lcEc=ξ, respectively. It is found that TD reaches its maximum and τD = τp as the energy of the tunnelling electron is equal to Ec/2, i.e. as lc =λDB, λDB is de Broglie wave length of the electron. 相似文献
17.
This paper reports that the optical emission spectroscopy (OES) is
used to monitor the plasma during the deposition process of
hydrogenated microcrystalline silicon films in a very high frequency
plasma enhanced chemical vapour deposition system. The OES
intensities (SiH\sj{*}, H微晶硅 VHF-PECVD 发射光谱学 薄膜物理学 microcrystalline silicon,
VHF-PECVD, optical emission spectroscopy 2005-11-09 2005-11-092005-12-12 This paper reports that the optical emission spectroscopy (OES) is used to monitor the plasma during the deposition process of hydrogenated microcrystalline silicon films in a very high frequency plasma enhanced chemical vapour deposition system. The OES intensities (Sill^*, H^* and H^*β) are investigated by varying the deposition parameters. The result shows that the discharge power, silane concentrations and substrate temperature affect the OES intensities. When the discharge power at silane concentration of 4% increases, the OES intensities increase first and then are constant, the intensities increase with the discharge power monotonously at silane concentration of 6%. The SiH^* intensity increases with silane concentration, while the intensities of H^*α and H^*β increase first and then decrease. When the substrate temperature increases, the SiH^* intensity decreases and the intensities of H^*α and H^*β are constant. The correlation between the intensity ratio of IH^*α/ISiH^* and the crystalline volume fraction (Xc) of films is confirmed. 相似文献
18.
Thickness-dependent magnetic properties in Pt/[Co/Ni]n multilayers with perpendicular magnetic anisotropy
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Chunjie Yan 《中国物理 B》2023,32(1):17503-017503
We systematically investigated the Ni and Co thickness-dependent perpendicular magnetic anisotropy (PMA) coefficient, magnetic domain structures, and magnetization dynamics of Pt(5 nm)/[Co($t_{\rm Co}$)/Ni($t_{\rm Ni}$)]$_{5}$/Pt(1 nm) multilayers by combining the four standard magnetic characterization techniques. The magnetic-related hysteresis loops obtained from the field-dependent magnetization $M$ and anomalous Hall resistivity (AHR) $\rho_{{xy}}$ showed that the two serial multilayers with $t_{\rm Co} = 0.2$ nm and 0.3 nm have the optimum PMA coefficient $K_{\rm U}$ as well as the highest coercivity $H_{\rm C}$ at the Ni thickness $t_{\rm Ni}= 0.6 $ nm. Additionally, the magnetic domain structures obtained by magneto-optic Kerr effect (MOKE) microscopy also significantly depend on the thickness and $K_{\rm U}$ of the films. Furthermore, the thickness-dependent linewidth of ferromagnetic resonance is inversely proportional to $K_{\rm U}$ and $H_{\rm C}$, indicating that inhomogeneous magnetic properties dominate the linewidth. However, the intrinsic Gilbert damping constant determined by a linear fitting of the frequency-dependent linewidth does not depend on the Ni thickness and $K_{\rm U}$. Our results could help promote the PMA [Co/Ni] multilayer applications in various spintronic and spin-orbitronic devices. 相似文献
19.
The dependences of soft magnetic properties and microstructures of the
sputtered FeCo (=FeFeCo薄膜 溅射条件 软磁性 高饱和磁化强度 FeCo film, sputtering conditions, high saturation magnetization,
soft magnetic properties 2005-10-26 3/7/2006 12:00:00 AM The dependences of soft magnetic properties and microstructures of the sputtered FeCo (=Fe65Co35) films on Co underlayer thickness tCo, FeCo thickness tFeCo, substrate temperature Ts and taxget-substrate spacing dT-s are studied. FeCo single layer generally shows a high coercivity with no obvious magnetic anisotropy. Excellent soft magnetic properties with saturation magnetization μ0Ms of 2.35 T and hard axis coercivity Hch of 0.25 kA/m in FeCo films can be achieved by introducing a Co underlayer. It is shown that sandwiching a Co underlayer causes a change in orientation and reduction in grain size from 70 nm to about 10 nm in the FeCo layer. The magnetic softness can be explained by the Hoffmann's ripple theory due to the effect of grain size. The magnetic anisotropy can be controlled by changing dT-S, and a maximum of 14.3 kA/m for anisotropic field Hk is obtained with dT-S=18.0 cm. 相似文献
20.
Degradation and its fast recovery in a-IGZO thin-film transistors under negative gate bias stress
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Jianing Guo 《中国物理 B》2021,30(11):118102-118102
A new type of degradation phenomena featured with increased subthreshold swing and threshold voltage after negative gate bias stress (NBS) is observed for amorphous InGaZnO (a-IGZO) thin-film transistors (TFTs), which can recover in a short time. After comparing with the degradation phenomena under negative bias illumination stress (NBIS), positive bias stress (PBS), and positive bias illumination stress (PBIS), degradation mechanisms under NBS is proposed to be the generation of singly charged oxygen vacancies ($V_{\mathrm{o}}^{+}$) in addition to the commonly reported doubly charged oxygen vacancies ($V_{\mathrm{o}}^{2+}$). Furthermore, the NBS degradation phenomena can only be observed when the transfer curves after NBS are measured from the negative gate bias to the positive gate bias direction due to the fast recovery of $V_{\mathrm{o}}^{+}$ under positive gate bias. The proposed degradation mechanisms are verified by TCAD simulation. 相似文献