Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 7443-7448 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Thermally stable, low-resistance p-type ohmic contacts have been developed by depositing NiInW metals on GaAs substrates in which Be and F were coimplanted. The contacts provided resistances of about 1.4 Ω mm after annealing at temperatures in the range of 300–800 °C for short times. The electrical properties did not deteriorate after annealing at 400 °C for more than 100 h, which far exceeds the requirements for current GaAs device fabrication. The present study demonstrated for the first time that thermally stable, low-resistance ohmic contacts to both n- and p-type GaAs can be fabricated using the same metallurgy. In addition, NiInW ohmic contacts were prepared by simultaneous (one-step) annealing for ion-implant activation and contact formation, which simplifies significantly the device fabrication process. A factor-of-2 reduction of the contact resistances was achieved by slight etching of the GaAs surface prior to the contact metal deposition so that the metal/GaAs interface contacted the peak position of the Be concentration in the GaAs substrate. Another method used to reduce the contact resistance was to add a small amount of Mn to the NiInW metals: the resistance decreased with increasing amounts of Mn. The contacts had smooth morphology and shallow depth, less than 70 nm, which is desirable for very-large-scale integration device application.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 68 (1990), S. 2468-2474 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The effects of Si or Ge addition to NiInW ohmic contacts on their electrical behavior were studied, where the samples were prepared by evaporating Ni(Si) or Ni(Ge) pellets with In and W and annealed by a rapid thermal annealing method. An addition of Si affected the contact resistances of NiInW contacts: the resistances decreased with increasing the Si concentrations in the Ni(Si) pellets and the lowest value of ∼0.1 Ω mm was obtained in the contact prepared with the Ni-5 at. % Si pellets after annealing at temperatures around 800 °C. The contact resistances did not deteriorate during isothermal annealing at 400 °C for more than 100 h, far exceeding process requirements for self-aligned GaAs metal-semiconductor field-effect-transistor devices. In addition, the contacts were compatible with TiAlCu interconnects which have been widely used in the current Si process. Furthermore, the addition of Si to the NiInW contacts eliminated an annealing step for activation of implanted dopants and low resistance (∼0.2 Ω mm) contacts were fabricated for the first time by a "one-step'' anneal. In contrast, an addition of Ge to the NiInW contacts did not significantly reduce the contact resistances.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 67 (1990), S. 6589-6591 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The outdiffusion of Be implanted into GaAs has been found to be identical after capless or capped (Si3N4 or SiO2 ) rapid thermal annealing (RTA) at 900–1000 °C and to depend on the Be dose and its proximity to the surface. The outdiffusion is more pronounced when the Be implant is shallow (〈0.1 μm) and/or the Be+ dose is high (〉1×1015 cm−2 ). It is demonstrated that the Be outdiffusion is driven by the presence of a highly damaged surface layer. Auger results suggest the formation of a BeOx compound at the surface of a high-dose (1×1016 cm−2 ) Be-implanted sample that underwent capless RTA at 1000 °C/1 s. It appears that BeOx formation occurs when the outdiffused Be interacts with the native Ga/As oxides during annealing. All the Be remaining in the GaAs after a 〉900 °C/2 s RTA is electrically active.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 2356-2364 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The influence of the GaAs surface condition on the properties and thermal stability of WNx Schottky diodes on GaAs has been studied by performing in situ H2 and N2 plasma treatments just before the WNx sputter deposition. The WNx/GaAs contacts have been investigated by x-ray photoelectron spectroscopy, Rutherford backscattering, nuclear reaction analysis, secondary ion-mass spectroscopy, x-ray diffraction, and transmission electron microscope and correlated to electrical current-voltage and capacitance-voltage measurements. A strong correlation was found between the diode properties and the surface conditions, both for the as-deposited samples and for samples annealed in the range 700–850 °C. Poor rectifying properties were obtained for the plasma-cleaned diodes due to the cumulative effects of plasma cleaning and sputter deposition. After annealing, improved characteristics were generally found. The highest Schottky barrier height values φI-V=0.76 V, which were found for the H2 plasma treated diodes annealed at 800 °C, were almost independent of the WNx composition and sputtering conditions. The H2 treated samples also showed the smoothest WNx/GaAs interface. HCl cleaned and N2 treated surface also showed high-barrier height and small interfacial reactions after high-temperature annealing.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 68 (1990), S. 2475-2481 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The electrical properties and microstructure of InAs ohmic contacts to n-type GaAs, prepared by sputter-depositing a single target, were studied by measuring the contact resistance (Rc) by the transmission line method and analyzing the interfacial structure by x-ray diffraction and cross-sectional transmission electron microscopy. Current-voltage measurement of an as-deposited InAs/W contact showed Schottky behavior, where the W layer was used as a cap layer. The InAs layer had an amorphous structure and a uniform oxide layer was observed at the InAs/GaAs interface. Even after annealing at 800 °C, ohmic behavior was not obtained in this contact because the intervening oxide layer prevented the InAs and GaAs interaction. By adding Ni to the InAs/W contacts (where Ni was deposited by an evaporation method), the interaction between the InAs and the GaAs was enhanced. Nickel interacted with As in the InAs layer and formed NiAs phases after annealing at temperature above 600 °C. The excess In in the InAs layer reacted with the GaAs substrate, forming InxGa1−xAs phases which covered about 80% of the GaAs interface. The Rc values of ∼0.4 Ω mm were obtained for InAs/Ni/W and Ni/InAs/Ni/W contacts at annealing temperatures in the range of 750–850 °C. These contacts contained only high melting point compounds and the contacts were stable during annealing at 400 °C for more than 100 h after ohmic contact formation.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 62 (1987), S. 2830-2835 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A WSix≈2.6 film was deposited by low-pressure chemical vapor deposition at 350–420 °C onto a P-doped polycrystalline silicon/SiO2/Si substrate. This polycide structure (with or without a subsequent As+ source/drain implant) was heat treated in the following manner: (i) 1000 °C/N2 anneal for 20 min, (ii) oxidation both in dry oxygen and in steam ambients at 920–950 °C (50 min–8 h), and (iii) N2 anneal as well as dry oxidation at 920 °C/50 min. Cross-sectional transmission electron microscopy, Rutherford backscattering, secondary ion mass spectrometry, and sheet resistance measurements were used for characterization. The as-deposited film was mostly amorphous with a fine grain structure. The N2 anneal caused the formation of a polycrystalline WSix〉2 film containing tetragonal WSi2. Dry oxidation produced a void-containing SiO2 layer atop the silicide film. However, the SiO2 layer was impregnated with W particles when the silicide film was steam oxidized. The role of excess Si in refractory metal silicide films during annealing and oxidation is discussed. The effect of stress at the corners of a step in a patterned wafer during the oxidation of tungsten polycide is also demonstrated.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 68 (1990), S. 5625-5629 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The effects of deposition temperature on growth, composition, structure, adhesion properties, stress, and resistivity of chemically vapor deposited W deposited purely by SiH4 reduction of WF6 are discussed. At lower deposition temperatures, due to incomplete Si reduction reaction, a small amount of Si is incorporated in the film. This elemental Si in W is responsible for the observed high stresses and high resistivities over a wide temperature range. With the increase in the deposition temperature, the conversion of incorporated Si as well as the initial Si reduction are taking place, stimulating increased grain growth and thereby relieving stress and reducing resistivity. The optimum values for stress and resistivity are achieved around 500 °C, as Si content is at its minimum. At higher temperatures the reaction between residual Si and W, is the prime cause of resistivity increase.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 67 (1990), S. 4183-4189 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The electrical properties and thermal stability of In/W Ohmic contacts in n-type GaAs were studied by analyzing interfacial microstructure using cross-sectional transmission electron microscopy and measuring the contact resistances by transmission line method. Indium layers with various thicknesses were deposited directly on GaAs substrates, which were kept at room or liquid-nitrogen temperature. The lower contact resistances (Rc) were obtained when the contacts were prepared at liquid-nitrogen temperature. These low Rc values were due to formation of large-areal InxGa1−xAs phases on the GaAs substrate after annealing at temperatures higher than 600 °C. The In layer thicknesses of the In/W contacts prepared at liquid-nitrogen temperature strongly affected the contact resistances as well as the thermal stability after contact formation. The optimum In layer thickness which provided the best electrical properties and thermal stability was determined to be 3 nm. The In(3 nm)/W contacts yielded Rc values less than 0.2 Ω mm and the Rc values did not deteriorate after annealing at 400 °C for more than 20 h. The contacts with In layer thicknesses thinner than 3 nm resulted in higher Rc values due to insufficient InxGa1−xAs phases at the metal/GaAs interfaces. The contacts with In layer thicknesses thicker than 3 nm resulted in poor thermal stability due to formation of large amounts of In-rich In(Ga,As) phases with low melting points. The present In(3 nm)/W Ohmic contacts are believed to be the simplest metallurgy with excellent electrical properties and thermal stability among In-based Ohmic contacts.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 51 (1987), S. 602-604 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A method is reported for reducing tunnel formation in p+-n Si, and a correlation is shown between tunnel defects and junction leakage. 11B+-implanted Si annealed for 30 min at 900 °C in N2 and subsequently deposited with W forms a high density of filamentary tunnel defects extending on the order of 0.1 μm from the W/Si interface. Reverse-bias leakage of 0.33-μm-deep junctions is −90 nA/cm2 at −5 V and the forward-bias ideality is 1.24 over eight decades of current. By contrast, for 11B+-implanted Si oxidized for 7 min in steam, tunnels if present are less than 0.01 μm in length. The reverse-bias leakage is −0.3 nA/cm2 at −5 V and the forward-bias ideality is 1.00. The 2×1019 cm−3 interfacial carrier concentration is the same for both deposits.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 57 (1990), S. 569-571 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: F+ co-implantation at different doses and energies was performed into GaAs already implanted with Be+ at high dose (1015 cm−2) and low energy (20 keV), in order to reduce the beryllium diffusion during post-implant annealing. The redistribution behavior of Be and associated electrical effects were studied by secondary-ion mass spectrometry, transmission electron microscopy (TEM), Hall effect measurements, and current-voltage profiling. Be outdiffusion was reduced by co-implantation of F; more than 80% of the implanted Be was retained during rapid thermal annealing up to 850 °C. The dose and energy of the F implant strongly influenced Be electrical activation efficiency. High activation, up to 48.5%, was obtained when F was co-implanted at high dose (1015 cm−2) and low energy (10 keV). Hole profiles shown reduced electrical activation in the region where F and Be profiles overlapped and TEM studies indicated the formation of {111} coherent plates, possibly BeF2 precipitates, in the same region. The reduction of Be outdiffusion in F co-implanted samples led to high activation after annealing, and was believed to be due to chemical interaction between Be and F.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...