Evaluation of ohmic contacts formed by B+ implantation and Ti-Au metallization on diamond

Venkatesan, V.; Malta, Dean; Das, K.; Belu, A. M.

doi:10.1063/1.354918

Cited by 54 publications

(22 citation statements)

References 24 publications

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“…9,10 Compared with the reported value, the c value that we obtained was high. This might be due to the contribution of the sputter defects, which could not be removed during the low-temperature annealing.…”

Section: ðCmsupporting

confidence: 49%

Ohmic contacts and interface properties of Au/Ti/p-diamond prepared by r.f. sputtering

Wang

Liu

Zhen

et al. 2000

Surf. Interface Anal.

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The Au/Ti/p-diamond contacts were prepared by r.f. sputtering and I-V measurements showed that the as-deposited contacts were ohmic. Upon annealing at 500°C for 10 min in a vacuum of 10 −4 Pa, the ohmic characteristics of the contacts were improved by 30%. The specific contact resistivity, which was calculated by the transmission line model (TLM), decreased from 2.9 × 10 −3 to 2.0 × 10 −3 Z·cm 2 as a result of post-deposition annealing. Analysis by XPS indicated the formation of titanium carbide at the Ti/diamond interface in the as-deposited and annealed states. This gave the contacts their good ohmic characteristics.

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Section: ðCmsupporting

confidence: 49%

Ohmic contacts and interface properties of Au/Ti/p-diamond prepared by r.f. sputtering

Wang

Liu

Zhen

et al. 2000

Surf. Interface Anal.

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“…3. Doping of diamond during growth or using ion implantation [5,6,10,11,12,13,14]. For example, to prepare good injecting contacts, several metals were used by Kozlov et aI., for hole injection they used Ag, Au, Pt or C deposition, aluminium or boron implantation, for electron injection P, Li or C [15].…”

Section: Iidevice Fabrication Issuesmentioning

confidence: 99%

Performance of monocrystalline diamond radiation detectors fabricated using TiW, Cr/Au and a novel ohmic DLC/Pt/Au electrical contact

Galbiati

Lynn

Oliver

et al. 2008

2008 IEEE Nuclear Science Symposium Conference Record

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Diamond radiation detectors are able to detect deep UV photons, X-rays, gamma rays, electrons, alpha particles, charged ions and neutrons, with a dynamic range in energies spanning from 5.5 eV up to GeV of cosmic rays. Since the bandgap of diamond is 5.5 eV this equates into negligible dark current noise at room temperature with no need for cooling. Metal diamond interfaces play a key role in the performance of the detectors as different metallization techniques lead to either ohmic or Schottky electrical contacts. We investigated the performance of synthetic high purity monocrystalline diamond radiation detectors fabricated with TiW, CrlAu and a novel metallization technique utilising diamond-like carbon tunnelling junction and PtlAu as electrical contacts. The investigation was carried out under irradiation with Co-60 y-rays, Sr-90 electrons and Am-241 a-particles. The experimental results with respect to I-V dark current levels, irradiation photocurrent, signal-to-noise ratio and time response have been compared and discussed. Results show an ohmic behaviour of the DLCIPtlAu contact, a charge collection efficiency of 100% at an applied electric field of 0.377 Vlum for all electrical contacts electrons irradiation) at a correspondent dark current value of less than a picoAmpere. The single crystal CVD DLCIPtlAu diamond radiation detector reported here shows spectroscopic energy resolution of 1.1% at an applied voltage of +450 volts under 5.5 MeV alpha particle irradiation; the experiments also showed a fast response of the novel contact with a transit time pulse of 6 ns . No 'memory' or 'pumping' effect was observed for the DLCIPtlAu contact at positive bias; the signal was also stable (fluctuations below 0.5%) and reproducible under Co-60 irradiation, with a signal to noise ratio > 10000:1 and a linearity in the dose rate response.

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“…Venkatesan et al 9 demonstrated ion-implanted ohmic contacts fabricated on CVD diamond using a dose of 3.5 ϫ 10 16 cm −2 . These structures contained a 0.2 m thick graphitized surface layer which was removed by etching and a Ti/ Au evaporated layer added to produce a low resistance ohmic contact ͑with a specific contact resistance of 1 ϫ 10 −4 ⍀ cm −2 ͒.…”

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confidence: 99%

Performance of a diamond x-ray sensor fabricated with metal-less graphitic contacts

Sellin

Galbiati

2005

Applied Physics Letters

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We report the x-ray photocurrent response of a coplanar chemical vapor deposition diamond detector fabricated using a metal-less graphitic ohmic contact. Ion implantation of 70 keV boron ions to a dose of 2 ϫ 10 16 cm −2 was performed through a patterned photoresist to produce a coplanar graphitic contact structure. The device photocurrent showed a fast response to pulsed x-ray irradiation, and showed no evidence of photocurrent persistence that is observed in devices fabricated using metal Schottky contacts. The graphite-contact device also showed no extrinsic photoconductivity when illuminated with white light. © 2005 American Institute of Physics. ͓DOI: 10.1063/1.2035885͔Chemical vapor deposition ͑CVD͒ diamond has considerable potential for use as a radiation sensor, particularly for deep ultraviolet ͑UV͒ and x-ray detection. Various authors have reported investigations of coplanar CVD diamond detectors as a tissue equivalent radiation dosimeter, and have demonstrated an x-ray photocurrent sensitivity similar to that of silicon photodiodes. The unique properties of diamond are well suited for this application, including extreme radiation hardness, high resistivity, and good charge transport. However the development of practicable diamond x-ray detectors has been restricted by a combination of priming effects and slow time response, or photocurrent persistence. These effects are due to a complex interplay between bulk trapping centers inherent in CVD material and the nature of the metaldiamond ohmic contacts used to fabricate the devices. In this work, we describe the performance of a coplanar x-ray sensor fabricated using a metal-less graphitized contact which was produced using a high dose implantation of boron ions. The interdigitated electrode structure was produced using only graphitized diamond, patterned by ion implantation through a photoresist.Two coplanar diamond devices were fabricated, using free-standing 70 m thick undoped polycrystalline CVD diamond film grown by Element Six Ltd. Device 1 consisted of a single coplanar electrode structure, with an electrode width and interelectrode gap of 100 m. The contacts were fabricated by a conventional photolithographic lift-off process, using thermally evaporated chromium ͑50 nm͒ followed by gold ͑200 nm͒. After lift off, the sample was annealed for 10 min at 400°C in a nitrogen atmosphere to form a metal-carbide contact. Device 2 was fabricated using ion implantation with no metal contact. Prior to implantation, a 2.5 m thickness photoresist was spun onto the diamond and patterned using a conventional optical mask. The mask design was divided into four quadrants, containing four coplanar devices with a central common electrode and with electrode widths and interelectrode gaps of 5 m, 10 m, 20 m, and 50 m ͑Fig. 1͒. A broad beam ion implantation was applied to the device at room temperature using 70 keV boron ions and a dose of 2 ϫ 10 16 cm −2 . After removal of the photoresist in acetone, the device was annealed for 4 min at 700°C in a nitrogen atmosphere ...

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Evaluation of ohmic contacts formed by B+ implantation and Ti-Au metallization on diamond

Cited by 54 publications

References 24 publications

Ohmic contacts and interface properties of Au/Ti/p-diamond prepared by r.f. sputtering

Ohmic contacts and interface properties of Au/Ti/p-diamond prepared by r.f. sputtering

Performance of monocrystalline diamond radiation detectors fabricated using TiW, Cr/Au and a novel ohmic DLC/Pt/Au electrical contact

Performance of a diamond x-ray sensor fabricated with metal-less graphitic contacts

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