摘要:

Buried oxynitride layers were formed in silica glass by N+only or both N+‐ and Si+‐ion implantation. These samples were characterized by secondary‐ion mass spectroscopy, Rutherford backscattering spectrometry, x‐ray photoelectron spectroscopy, and scanning electron microscope. The depth profile of implanted N without Si implantation is a trapezoidal shape at a high‐dose condition (more than about 3 × 1016ions/cm2). In the N+implantation only, a part of implanted N reacts with Si, and forms a SiON layer which is thermally unstable. In both Si+(100 keV, 1 × 1017ions/cm2) and N+(50 keV, 11× 1017cm2) implantation, the depth profile of N is a Gaussian distribution, and the thermal stability of a SiON layer is dramatically improved. However, bubbles were generated near the projected range of Si and N at a high‐dose condition (the total dose was 4 × 1017ion/cm2and the dose ratio Si/N=3/4). The generation of bubbles was suppressed by two‐step N+implantation (40 and 60 keV).

ISSN:0021-8979    

DOI:10.1063/1.346329

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

TheGvalue refers to the number of molecules of reactant consumed or product formed per 100 eV of energy absorbed. Although ubiquitous in radiation chemistry, theG‐value concept appears only rarely in plasma chemistry. We derive a formula for theGvalue for a general plasma chemical reaction as a function of the electrical power absorbed, the fraction of molecules transformed, and the flow rate of the gas entering the reactor. Applying our formula to the ammonia plasma radiofrequency discharge data of d’Agostinoetal. [Plasma Chem. Plasma Process.1, 19 (1981)], we find thatG(‐NH3) depends in general upon the conditions but lies in the range of 6.0–20 molecules/100 eV. By comparison, the values ofG(‐NH3) reported by Peterson for the gas‐phase radiolysis of ammonia lie in the range 2.7–10 molecules/100 eV. We suggest that this similarity with respect to order of magnitude may have its origin in a common reaction mechanism initiated by inelastic electron‐molecule collisions. We use this hypothesis and the Boltzmann transport theory to derive a formula which expressesG(‐NH3) in terms of electron‐molecule scattering cross sections, the distribution of electron velocities, and the rate constants for secondary reactions. In principle, given a knowledge of the reaction mechanism and the electron‐energy‐loss channels, our method may be used to express theGvalue of any gas.

ISSN:0021-8979    

DOI:10.1063/1.346330

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The adsorption and decomposition of PH3on Si(111)‐(7×7) was investigated in ultrahigh vacuum by means of temperature programmed desorption, low‐energy electron diffraction, Auger electron spectroscopy (AES), and electron stimulated desorption (ESD) methods. Phosphine adsorbs on Si(111)‐(7×7) atT=120 K with an initial sticking coefficient ofS0&bartil;1 through a mobile (extrinsic) precursor state. Some PH3dissociative adsorption at 120 K is observed. Thermal activation of the adsorbed species results in desorption of a molecular PH3species up to 550 K. Further heating produces H2(g) desorption atT&bartil;740 K and P2(g) desorption atT&bartil;1010 K, thus indicating that PH3decomposition has occurred. AES and ESD studies of the adsorbed species reveal that decomposition takes place by the breaking of PH bonds in PHx(a) to form SiH species on the surface for 120 K<T<700 K.

ISSN:0021-8979    

DOI:10.1063/1.347168

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

This paper is concerned with a detailed analysis of the dominant modes of a slotted helix loaded in an empty waveguide, with a view to improving the efficiency of plasma production using such structures. To this end the dispersion relation for a slotted helix loaded inside a cylindrical waveguide is first derived. As in the case of a tape‐helix‐loaded waveguide, the different dominant modes of the system can be identified by suitable asymptotic expansions of the exact dispersion relation. For large diameter helices (kvrh>1, wherekvis the free‐space wavelength of the wave andrhis the helix radius), the system has one slow wave and one fast wave as its dominant waves. The field patterns of these two modes are studied (for both slotted and tape helices) and the dominant field components corresponding to each type of helix and mode, identified from the point of view of ease in the excitation of the slow wave for plasma production. Since the fast and slow waves have overlapping dominant field components, methods are also discussed for suppressing the fast wave which can be excited more easily due to the presence of the waveguide. Finally, the state of polarization (left/right handedness) of the slow‐wave mode is discussed with relevance to the coupling of the microwave to the plasma electrons in an external magnetic field.

ISSN:0021-8979    

DOI:10.1063/1.346331

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

Several diacetylenic lecithins form tubular microstructures (tubules) when their liposomes are cooled through the chain‐melting transition. Recently, the tubules have been metal plated by an electroless technique. This paper reports on the interaction of permalloy coated tubules with electromagnetic radiation. At 10 vol % loading of tubules in an epoxy matrix has a real dielectric constant &egr;’≊50 at a frequency of 9.5 GHz. Simple electrodynamics accounts well for the observed results. Far higher values of &egr;’may be achievable with longer tubules and with improved metal coatings.

ISSN:0021-8979    

DOI:10.1063/1.346332

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

An analysis of silicon metal‐oxide‐semiconductor (MOS) transistor operation at liquid‐helium temperature is presented. More specifically, analytical models providing the drain current and transconductance characteristics in the linear and nonohmic regions are established in the presence of source‐drain series resistances. These models, which rely on a specific mobility law for very low temperature, enable a good description of MOS transistor operation to be obtained. They permit the understanding and the prediction of the effects of source‐drain series resistance both in the linear and nonlinear regions. Furthermore, they allow a suitable parameter extraction method to be developed for the liquid‐helium temperature range. In addition, peculiarities of the drain voltage dependence of the mobility at low longitudinal electric field are also pointed out and empirically accounted for in the modeling of the output characteristics.

ISSN:0021-8979    

DOI:10.1063/1.346333

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

The high‐performance AuCr/SiO2/InSb metal‐oxide‐semiconductor capacitor was fabricated successfully using photoenhanced chemical vapor deposition. The 1200‐A˚‐thick SiO2layer was deposited on the InSb substrate at a temperature below 200 °C. Their electrical and structural properties were analyzed by capacitance‐voltage and Auger electron spectroscopy, respectively. The capacitance‐voltage results show that the optimal growth temperature of SiO2is 150 °C at which the flat‐band voltage of the capacitor is close to ideal and the slow interface state density is less than 5 × 1010cm−2. For SiO2deposited at a lower temperature, although the flat‐band voltage and interface state are poorer, the subsequent thermal annealing at 150 °C for 12 h improves both quantities to the level as the optimal condition. However, for SiO2deposited at a higher temperature (190 °C), the flat‐band voltage shifts to −4 V and the slow state density increases to 1.1 × 1011cm−2. It is found from the Auger depth profile that whatever the deposition temperature was a Si‐rich region followed by an oxygen‐rich region was formed at the SiO2/InSb interface. These observations are shown to be consistent with the electrical characteristics of the capacitor.

ISSN:0021-8979    

DOI:10.1063/1.346334

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

We describe reverse bias diode leakage and physical analysis (secondary ion mass spectroscopy, Rutherford backscattering and transmission electron microscopy) data from shallowp+/njunctions made by implanting various doses of BF2into polycrystalline Si and out‐diffusing at various temperature/time conditions, into the underlying (100) Si substrate. The polycrystalline Si is cobalt disilicided to provide the first level of metallization. Subsequent metallization consists of electroless plated Co followed by sputtered Al. The minimum process specifications giving good junction quality (reverse bias diode leakage current density ≤10 nA/cm2at 10 V) are 5×1015cm−2BF2outdiffused at 900 °C, 30 min with a junction depth 1200 A˚ below the polycrystalline Si. At these conditions, most of the BF2(>90%) uniformly redistributes in the polycrystalline Si. There is a slight increase in B concentration towards the polycrystalline Si/Si interface which is characterized by a porous, <50‐A˚ thin silicon oxide interface. The polycrystalline Si/Si interface is also characterized by a peaked fluorine concentration. The lower boron dose diffusing into the Si substrate may be used to explain the observation that thesep+/ndiodes are ∼10 times leakier than similarn+/pdiodes made by outdiffusing As or P implanted from the polycrystalline Si diffusion source.

ISSN:0021-8979    

DOI:10.1063/1.346335

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

We describe reverse bias diode leakage and physical analysis (secondary ion mass spectroscopy, Rutherford backscattering and transmission electron microscopy) data from shallown+/pjunctions made by implanting various doses of arsenic into polycrystalline Si and out diffusing at various temperature/time conditions, into the underlying (100) Si substrate. The polycrystalline Si is cobalt disilicided to provide the first level of metallization. The minimum process specifications giving good junction quality (reverse bias diode leakage current density ≤10 nA/cm2at 10 V) are 7×1015cm−2As out diffused at 950 °C, 30 min with a junction depth 1200 A˚ below the polycrystalline Si. At these conditions, most of the As (≳90%) uniformly redistributes in the polycrystalline Si. There is a segregation to the polycrystalline Si/Si interface which is characterized by a porous, <50 A˚ thin silicon oxide interface. The polycrystalline Si/Si interface is also characterized by a laterally non‐uniform large grain(∼2000 A˚) or epitaxial regrowth at the 950 °C process temperature. These interface conditions may be used to explain the ∼20% high leakage population which is independent of out‐diffusion condition at high As dose. Such a high sport population is not observed when P is implanted into polycrystalline Si and out diffused at 900 °C, 30 min to obtain ∼2500‐A˚‐deep junctions below the polycrystalline Si/Si interface.

ISSN:0021-8979    

DOI:10.1063/1.346309

出版商:AIP    

年代:1990

数据来源: AIP

摘要:

We report the anomalous Hall effect and nonuniformities introduced by aging in the bulk polycrystalline HgTe, which was grown in a predetermined profile, and measurements were taken in the temperature range of 82–350 K. It is found that anomalous behavior is caused by domain formation which is due to acceptor states and this domain formation effect gets diminished by annealing the sample in a mercury atmosphere.

ISSN:0021-8979    

DOI:10.1063/1.346310

出版商:AIP    

年代:1990

数据来源: AIP