摘要:

Copper may become an alternative to aluminum as an interconnect material in ultralarge scale integration multilevel metallization schemes if it is possible to pattern Cu by dry etching in a manufacturable process. Here we report results on the reactive ion etching of Cu in SiCl4/Ar and SiCl4/N2plasmas. Etching has been investigated as a function of gas composition, pressure, and substrate temperature. We have obtained etch rates as high as 850 A˚/min using SiCl4/N2and a substrate temperature of ∼ 220 °C, with excellent etch selectivity of Cu relative to polyimide and SiO2. We demonstrate that it is feasible to pattern Cu anisotropically using polyimide as a high‐temperature etch mask.

ISSN:0003-6951    

DOI:10.1063/1.106299

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

A novel method of creating ultrathin, well‐ordered organic multilayer films is described, in which freely suspended smectic liquid crystal films are transferred to solid substrates. X‐ray and optical measurements show that both the smectic layering and the in‐plane director field, which are the defining characteristic structures of the original free film, are maintained after transfer. This method, in contrast to traditional techniques of organic film deposition, offers the possibility of orienting the initial freely suspended liquid crystal films using applied fields to obtain highly organized monodomain structures after transfer.

ISSN:0003-6951    

DOI:10.1063/1.106300

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

The driving force for the introduction of dislocations at the interface between a strained buffer layer and its substrate is considered. An exact assessment is made of the difference in energy between a system in which prestrain is partially relaxed by the presence of a periodic array of dislocations between layer and substrate and one containing a periodic array which is complete except for one vacant site. The difference provides an expression for the driving force, for introducing the ‘‘last’’ dislocation to complete the periodic array, by the motion of a threading dislocation. All of the dislocation stress fields are accounted for exactly. It emerges that, contrary to intuition, the fluctuating part of the dislocation stress field contributes a term which is attractive rather than repulsive, which is the opposite effect to that found in ‘‘Taylor hardening.’’

ISSN:0003-6951    

DOI:10.1063/1.106301

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Coimplantation effects of phosphorus (P) are studied for Si‐implanted GaAs by photoluminescence and secondary‐ion mass spectrometry. P coimplantation decreases SiAsacceptor intensity. At high temperatures rapid thermal annealing causes As loss, which favors the formation of the SiAs‐VAscomplex. Diffusion of Si towards the GaAs bulk is not caused by P coimplantation but rather by the presence of carbon.

ISSN:0003-6951    

DOI:10.1063/1.106302

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We studied the lifetimes of photoexcited carriers in H+bombarded InP for different damage doses by means of femtosecond luminescence spectroscopy. The lifetime decreases down to 95 fs for a dose of 1×1016cm−2. To our knowledge this is the shortest decay time for spontaneous light emission ever observed. The luminescence spectrum of the most damaged sample is inverted, indicating nonthermalized carrier distributions.

ISSN:0003-6951    

DOI:10.1063/1.106303

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

<m1;40p>Tungsten nitride thin films are prepared with the WF6‐NH3‐H2system by the plasma‐enhanced chemical vapor deposition method. X‐ray diffraction and Auger spectroscopy show that the crystal structure and the composition of tungsten nitride thin films grown at the WF6/NH3ratio of 1 are &bgr;‐phase W2N. The resistivity of W2N is about 190–210 &mgr;&OHgr; cm and it is demonstrated that severe encroachment and SiO2etching during the low‐pressure chemical vapor deposition of tungsten is remarkably suppressed by the predeposition of W2N.

ISSN:0003-6951    

DOI:10.1063/1.106304

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Undoped semi‐insulating (SI) InP wafers were obtained by high‐temperature annealing under high phosphorus over pressure. These wafers show resistivities higher than 107&OHgr; cm, with mobilities greater than 4000 cm2 V−1 s−1. The SI properties could be held even after cap annealing with SiNxfilms at 700 °C for 15 min. The activation energy of deep levels causing the semi‐insulation was estimated as 0.64 eV. Photoluminescence measurements made on undoped SI InP show hitherto unknown peaks in the long wavelength region between 1000 and 1400 nm.

ISSN:0003-6951    

DOI:10.1063/1.106305

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Pulsed laser ablation of an aluminum target at 193, 248, and 351 nm has been investigated by laser‐induced fluorescence (LIF) spectroscopy. Velocity distributions of the ablated Al atoms have been measured directly by monitoring their flight times from the target to the probe laser beam, and by Doppler laser spectroscopy. The velocity distributions resulting from the three wavelengths can all be characterized as hyperthermal, with average velocities of between 4.5×105and 6.5×105cm/s over a fluence range of 0.3–6.5 J/cm2. Average values of the Al atom distribution can also be derived by measuring the AlO internal energy distribution of the ‘‘hot’’ Al atom reaction with low pressures of O2. For excimer laser ablation of aluminum at 248 nm, we have found an average Al atom velocity of ≳2×105cm/s. Possible mechanisms for the production of these hyperthermal velocity distributions are discussed.

ISSN:0003-6951    

DOI:10.1063/1.106306

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

The interaction of mercury vacancies with dopant indium atoms in Hg0.79Cd0.21Te was studied using the perturbed &ggr;&ggr; angular correlation (PAC) technique. Two dominant PAC signals, characterized by quadrupole interaction strengths &ngr;Q1=83 MHz and &ngr;Q2= 91 MHz and asymmetry parameters &eegr;1=&eegr;2=0.08, were observed and attributed to one or more In‐VHgcomplexes. The complexes appeared after annealing doped samples atT≥350 °C in vacuum and quenching. The fraction of In atoms associated with vacancies was increased further by annealing at 80 °C for ≳10 h. The In‐vacancy complexes vanished on annealing in a Hg‐saturated atmosphere.

ISSN:0003-6951    

DOI:10.1063/1.106307

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Nonintentionally doped metalorganic vapor‐phase epitaxy Ga1−xInxP layers, having an alloy composition (x= 0.49) corresponding to a lattice matched to GaAs, grown by metalorganic chemical vapor deposition, have been studied by capacitance‐voltage and deep‐ level transient spectroscopy techniques. They are found to exhibit a free‐carrier concentration at room temperature of the order of 1015cm−3. Two electron traps have been detected. The first one, at 75 meV below the conduction band, is in small concentration (∼ 1013cm−3) while the other, at about 0.9 eV and emitting electrons above room temperature, has a concentration in the range 1014–1015cm−3.

ISSN:0003-6951    

DOI:10.1063/1.106308

出版商:AIP    

年代:1991

数据来源: AIP