Effect of incident laser fluence on the structure of pulsed-laser deposited AlN films

A. Szekeres, S. Simeonov, S. Bakalova, I. Minkov, A. Cziraki, C. Ristoscu, G. Socol, G. Dorcioman, I. N. Mihailescu

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Polycrystalline AlN films were synthesized on (100)Si substrates by pulsed laser deposition at 800°C and different incident laser fluences and nitrogen ambient pressures. We used two KrF* (λ= 248 nm) excimer laser sources generating pulses of 7.4 and 25 ns duration, respectively. The incident laser intensity was kept constant in all experiments within the range (3 - 4) × 108 W/cm2. The effect of incident laser fluence on the structure and defects of pulsed laser deposited AlN films was investigated by X-Ray diffractometry and frequency-dependent admittance measurements at zero DC bias voltage. The X-ray diffraction results revealed a polycrystalline structure with predominantly cubic crystallites in films deposited with short laser pulses (laser fluences of 2.5 and 3.7 J/cm2, respectively). With longer laser pulses and large fluence (8.6 J/cm2), the prevalent crystalline phase changed from cubic to hexagonal. For intermediate deposition conditions (long pulses and lower fluences), the co-existence of the two crystalline phases was recorded. In addition, the admittance measurements in the frequency range of 1 kHz-20 MHz evidenced the contribution of deep levels to the frequency dispersion of the capacitance and current conductance of AlN MIS structures.

Original languageEnglish
Pages (from-to)542-546
Number of pages5
JournalJournal of Optoelectronics and Advanced Materials
Volume12
Issue number3
Publication statusPublished - Mar 2010

Keywords

  • AC conductivity mechanism
  • Crystalline aluminium nitride thin films
  • Pulsed laser deposition
  • Structure and defects

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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  • Cite this

    Szekeres, A., Simeonov, S., Bakalova, S., Minkov, I., Cziraki, A., Ristoscu, C., Socol, G., Dorcioman, G., & Mihailescu, I. N. (2010). Effect of incident laser fluence on the structure of pulsed-laser deposited AlN films. Journal of Optoelectronics and Advanced Materials, 12(3), 542-546.