电子辐照硅层中缺陷能级的研究

用12MeV电子辐照硅p⁺n结,在硅中除引入氧空位E₁(E_c-0.19eV),双空位E₂(E_c-0.24eV)和E₄(E_c-0.44eV)外,还引入缺陷E₃(E_c-0.37eV)。用DLTS方法和反向恢复时间测量研究了这些能级的退火行为,可以看到,E₃的退火温度最高(≈520℃)。由退火特 关键词：     

拍波激光加速器中的频率匹配

本文从广义协变的运动方程和麦克斯韦方程出发,导出了电子等离子体波各量的解析表达式。指出△ω=2ω_p的等离子体波是完全简谐的。完全共振的条件由△ω=2ω_(p0)[1+(e²(A₂⁽⁽¹⁾²⁾+(A₂^((2)2))/(2m²c⁴)+(3e²A₂⁽¹⁾A₂⁽²⁾)/(m²c⁴)]^-1/2 给出。 关键词：     

硅中三空位V3-的超精细相互作用的理论计算

利用Koster-Slater的格林函数方法,计算了硅中三空位V₃^-的电子态能级和波函数.结果表明,V₃^-在禁带中有五条能级:E_(A2)=0.417eV,E_(B1)=0.492eV,E_(B2¹)=0.512ev, E_(A1)=0.532eV,E_(B2²)=0.608eV.根据算得的超精细相互作用常数同实验值的比较,定出V₃^-处于B₁态.V₃^-的B₁态点据第1壳层的几率为60.2％,但主要集中在三空位所确定的平面内的二个原子上. 关键词：     

高温电子辐照硅中缺陷的研究

本文对高温电子辐照硅中产生的缺陷进行了研究,发现缺陷的引进率随电子辐照温度的增加而增加,在达到极值温度T_m后,缺陷的引进率将随之而下降,T_m值与缺陷的退火激活能有关。E₃缺陷(E_c—0.36eV)浓度在高温电子辐照中显著增加,在330℃高温电子辐照时,E₃缺陷浓度为室温电子辐照的6倍。研究结果表明,E₃缺陷的可能结构为与多空位和氧有关的复合体。 关键词：     

激光拍频波加速器的参数选择

本文研究了激光拍频波加速器中的三波相互作用过程。结果表明:适当地选择参数σ=ω_p/(ω₁-ω₂)以及β=ω₂/ω₁(ω_p,ω₁,ω₂分别为等离子体频率及两束激光频率),即可用较弱的激光造成很强的拍频等离子体波,并使注入等离子体的电子获得显著的能量增益。 关键词：     

注硅半绝缘GaAs的深能级

用深能级瞬态谱(DLTS)详细研究了硅离子注入Liquid-encapsulated Czochralski(缩写为LEC)半绝缘GaAs的深中心。结果表明,在注硅并经高温退火的有源区中观测到4个多子(电子)陷阱,E₀₁,E₀₂,E₀₃和E₀₄。它们的电子表观激活能分别为0.298,0.341,0.555和0.821eV。其中E₀₄与EL2有关,但不是EL2缺陷。E₀₄的电子 关键词：     

硅中Jahn-Teller畸变的双空位超精细相互作用的理论计算

采用扩展的Koster-Slate模型,分别对硅中双空位的两种重要的Jahn-Teller畸变模,计算了缺陷电荷态V₂⁺,V₂^-中未配对电子的超精细相互作用常数a和b,给出与实验符合得很好的结果.由此还定出与实验相符合的能级和对称态:V₂⁺的未配对电子处于能级约为0.3eV的Ag对称态;而V₂^-的电子处于能级约为0.63eV的Bu态;EG1模可能是V₂⁺和V₂^-的最优选的畸变. 关键词：     

N2微空心阴极放电特性及其阴极溅射的PIC/MC模拟

采用两维PIC/MCC模型模拟了氮气微空心阴极放电以及轰击离子 (N₂⁺,N⁺) 的钛阴极溅射. 主要计算了氮气微空心阴极放电离子 (N₂⁺,N⁺) 及溅射原子Ti的行为分布, 并研究了溅射Ti 原子的热化过程. 结果表明: 在模拟条件下, 空心阴极效应是负辉区叠加的电子震荡; 在对应条件下, 微空心较传统空心放电两种离子 (N₂⁺,N⁺) 密度均大两个量级, 两种离子的平均能量的分布及大小几乎相同; 在放电空间N⁺的密度约为N₂⁺的1/6, 最大能量约大2倍; 在不同参数 (P, T, V)下, 轰击阴极内表面的氮离子(N₂⁺,N⁺)的密度近似均匀, 其平均能量几乎相等; 从阴极溅射出的Ti原子的初始平均能量约6.8 eV, 离开阴极约0.15 mm处几乎完全被热化. 模拟结果为N₂微空心阴极放电等离子体特性的认识提供了参考依据. 关键词： 微空心阴极放电 PIC/MC模拟 2等离子体')" href="#">N₂等离子体     

n型气相外延GaAs层中中子辐照感生缺陷的研究

本文研究了1MeV中子辐照在气相外延n-GaAs有源层中深能级缺陷的特性和热退火性能。结果表明,大多数感生缺陷是与两个以上原子位移有关的缺陷。另外,当H₁能级通火时,出现了一个新的缺陷能级E₅(E_c-0.73eV)。研究表明GaAs MESFET参数的变化主要是由于载流子去除。 关键词：     

关于超导临界温度级数收敛半径的一个注记

本文指出,对于实际的归一化有效声子谱函数g(ω),一般来说,z_ph≡F(-ω_ph^-2是函数z=F(y)≡∫₀^(ω_ph)(ω²y)/(ω²y+1)g(ω)dω的反函数的分支点。因此,在估算超导T_c级数的收敛半径时,应当予以考虑。 关键词：     

Optical properties of electron irradiation induced defects in InP

The optical properties of deep hole traps H₄ and H₅ in p type and of the deep electron trap E₁₁ in n type InP, introduced by electron irradiation, have been studied using deep level optical spectroscopy. Comparison of the optical threshold with the thermal activation energy of H₅ level shows that it is highly relaxed with a Frank-Condon shift d_Fc = 0.45 eV. The electron level E₁₁ is weakly relaxed and its optical cross section σ ⁰ is well accounted for by transitions to the Γ_6c minimum. The optical absorption σ_p⁰ associated to level H₄ shows two successive onsets at hν = 0.5 and hν = 1.2 eV which can be attributed to hole transitions to the Γ_7–8 and to the L_4–5 valence band extrema, respectively. The deduced Frank-Condon shift, d_Fc = 0.23 eV, agrees with the measured difference of 40 meV between its apparent activation energy E_a and its thermal activation energy E_T.     

Inductively coupled plasma induced deep levels in epitaxial n-GaAs

The electronic properties of defects introduced by low energy inductively coupled Ar plasma etching of n-type (Si doped) GaAs were investigated by deep level transient spectroscopy (DLTS) and Laplace DLTS. Several prominent electron traps (E_c—0.046 eV, E_c—0.186 eV, E_c—0.314 eV. E_c—0.528 eV and E_c—0.605 eV) were detected. The metastable defect E_c—0.046 eV having a trap signature similar to E1 is observed for the first time. E_c—0.314 eV and E_c—0.605 eV are metastable and appear to be similar to the M3 and M4 defects present in dc H-plasma exposed GaAs.     

DLTS and PTIS of new donors in oxygen-doped germanium

Two new DLTS bands I and II have been observed in n-type germanium containing 10¹⁶ cm^-3 interstitial oxygen. The signature of II is: E_c?E_II = 0.031 eV, K = 4 × 10⁷ cm^?2s^?1; level I is about half as deep. In addision, the excitation spectrum of I is recorded by PTIS. It is composed of three hydrogenic donor series Ia, b, c with activation energies 17.25, 17.6 and 18.1 meV. The donors I and II are thought to correspond with the well known thermal oxygen donors. Energies for the latter were determined at 0.017 and 0.04 eV from Hall effect by Fuller and Doleiden. The possibility of double donors is examined, in analogy with the case of oxygen donors in silicon.     

The defects produced by electron irradiation in tellurium-doped germanium

Abstract

The nature of the irradiation induced defects in germanium single crystal doped with tellurium was studied by DLTS and electrical measurements.

The E_c-0.21 eV level produced by irradiation with 1.5 MeV electrons was studied by DLTS technique. It was found that the defect associated with the E_c-0.21 eV level is divacancy. The E-center like defect (group V impurity-vacancy pair) introduces the E_c-0.20 eV level in samples doped with group V impurity. The level introduced by tellurium (group VI impurity)-vacancy pair is located at deeper than E_c-0.21 eV.

The E_c-0.16 eV level was generated by the annealing at 430 K. A model for the defect associated with the level is proposed to be a tellurium-vacancies complex.     

An interpretation of dlts spectra of Al/Si3N4/ultrathin SI/GaAs structures — Effect of quantum well or interface states?

We discuss DLTS andC-V measurements on Al/Si₃N₄/Si(2nm)/n-GaAs (≈ 5×10¹⁷ cm^?3) structures. Three discrete deep traps superimposed on a U-shaped interface-state continuum have been identified, with respective thermal energies:E _c?0.53 eV,E _c?0.64 eV, andE _v+0.69 eV. The second one (0.64 eV) is presented as an electric field sensitive level, its enhanced phonon-assisted emission resulting in a rapid shift of the corresponding DLTS peak to lower temperatures, as the applied (negative) reverse bias voltage increases. An interpretation through emission from the quantum well, introduced by means of the intermediate ultrathin Si layer, has failed.     

Defect annealing in phosphorus implanted silicon: A D.L.T.S. study

Deep-level transient spectroscopy (D.L.T.S.) has been applied to the determination of defects in ion implanted silicon. Preliminary results concerning defects introduced by 130 KeV phosphorous ion implantation are described. Four electron traps are found: atE _c -0.21 eV,E _c -0.39 eV,E _c -0.52 eV andE _c -0.58 eV and their cross-sections estimated. The annealing behaviour in the range 450–800°C of these traps is described. Work supported in part by the Institute of Physics, Polish Academy of Science, Warsaw. Laboratoire associé au C.N.R.S.     

Temperature dependent photoluminescence of PECVD a-SiOx:H (x<2)

The temperature dependent visible photoluminescence (PL) property of a-SiO_x:H (x<2) samples prepared in a PECVD system by using SiH₄+CO₂ gas mixture is investigated at a temperature range of 20 K-400 K. One of the two explicitly distinguished PL bands, with varying peak photon energies between 1.70 and 2.05 eV, can be detected at only low temperatures below 200 K, which is attributed to tail-to-tail radiative recombination. Thermal quenching parameter (T_L) of the tail-to-tail PL band is calculated as varying between 120 and 280 K as the atomic oxygen concentration ([O]at.%) of the samples increases. Stokes shift (ΔE_Stokes) of the tail-to-tail PL band is found to change from 85 meV to 420 meV due to band tail widening. The other PL band emerges at 2.1 eV and can be detected at higher temperatures with thermal activation behavior. The activation energies calculated about room temperature vary in the range of 8 meV-50 meV with oxygen concentration. Thermal activation of the 2.1 eV PL band is attributed to the behavior of thermally activated incoherent hopping migration of electrons. These electrons combine with self trapped holes (STHs) to form self trapped excitons (STEs). STEs are localized at intrinsic defects of SiO₂ structure such as oxygen vacancies (E′ centers) and non-bridging oxygen hole centers (NBOHC).     

Stress-induced X1c-X3c conduction band mixing in GaP

We present the first investigation of the stress-induced coupling between X_1c and X_3c conduction band minima in zincblende type semiconductors. The high uniaxial stress values achieved in this work (X= 19 kbar) enable us to observe a nonlinear behavior of the X_1c minima due to the stress-induced X_1c-X_3c coupling. This coupling is described by a single deformation potential 6E₃6 = 13 eV.     

Photoluminescence measurements of the 1.55 eV band of Ge doped AℓxGa1−xAs

The photoluminescence of the 1.55 eV band of Ge doped A?_xGa_1?xAs, with x=0.30–0.33, grown by liquid phase epitaxy is presented. The broad shape was found to be due to a lattice relaxation upon optical transitions. Resonant modes with ?ω_q = 35±2 meV and ?ω_q = 45±2 meV are found for the optical band, yielding a zero phonon transition energy = 1.73±0.02 eV and a Franck-Condon shift = 0.17–0.20 eV for the optical center. The activation energy of thermal quenching yields an associated donnor binding energy of 0.17±0.04 eV. Possible mechanisms for the radiative transitions are discussed.