9-13 July 2012
DLTS and I-V-T characteristicsof e-beam deposited Pd/W 4H-SiC Schottky contacts
Presented by Mr. Alexander PARADZAH on 12 Jul 2012 from 17:30 to 19:30
Type: Poster Presentation
Session: Poster Session
Track: Track A - Division for Condensed Matter Physics and Materials
DLTS investigations of 4H-SiC homo-epitaxial layers of doping density ~ (10<sup>14</sup> – 10<sup>16</sup>) cm<sup>-3</sup> reveal the presence of two peaks below the conduction band, E<sub>C</sub>, which we attribute to the e-beam metallization damage: at (E<sub>C</sub> – 0.160) eV and at (E<sub>C</sub> – 0.121) eV. These peaks were, however, not observed in 10<sup>16</sup> cm<sup>-3</sup> material. In addition, the well-known peaks at (E<sub>C</sub> – 0.096) eV and at (E<sub>C</sub> – 0.607) eV were present in all our samples in the doping range investigated. We observed departure from thermionic-emission (TE) theory in the I–V–T characteristics in the temperature range 30 K ≤ T ≤ 340 K, confirming the surface damage and indicative of an inhomogenous Schottky barrier at the W/SiC interface. Both the Schottky barrier height (ф<sub>BO</sub>) and the diode ideality factor (n) exhibited anomalous behaviour: typically in 10<sup>16</sup> cm<sup>-3</sup> doped SiC, 1.50 eV ≤ ф<sub>BO</sub> ≤ 0.89 eV and 1.10 ≤ n ≤ 4.60 were observed, respectively, with decreasing measurement temperature. The inhomogenous Schottky barrier was satisfactorily described by a Gaussian distribution with mean ф<sub>BO</sub> = 1.30 eV and standard deviation σ<sub>0</sub> = 0.002 eV. Current conduction was predominantly TE for T > 100 K and was increasingly of a thermionic-field-emission (TFE) character for T < 100 K.
F D AURET, email@example.com, University of Pretoria