Determining the Richardson constant of Ni/4H-SiC and W/4H-SiC Schottky diodes via Current-Voltage-Temperature (IVT) characteristics
Presented by Ms. Asmita SINGH on 9 Jul 2014 from 17:10 to 19:00
Type: Poster Presentation
Track: Track A - Division for Physics of Condensed Matter and Materials
Board #: A.34
In this project the Richardson constant (<i>A<sup>*</sup></i>) for metal-semiconductor contacts on 4H-SiC was investigated by means of current-voltage measurements as a function of temperature in the range of 300 K to 700 K. Multiple <i>n</i>-type 4H-SiC-based metal-semiconductor contacts, having an estimated carrier concentration of 3.70 x 10<sup>14</sup> cm<sup>-3</sup> were considered. The current-voltage-temperature (IVT) characteristics of Ni/4H-SiC and W/4H-SiC Schottky barrier diodes were studied, based on the thermionic emission model. The samples were prepared using various deposition techniques, (viz. Ni – resistive evaporation and electron-beam deposition (EBD); and W – RF sputtering and EBD) and diode parameters (such as ideality factor (<i>η</i>), Schottky barrier height (<i>Ф<sub>B</sub></i>), series resistance (<i>R<sub>s</sub></i>) and saturation current (<i>I<sub>s</sub></i>)) obtained were compared and found to be strongly dependent on temperature. The Richardson constant for 4H-SiC obtained from the intercept of a least squares fit through the Arrhenius plot data resulted in 3.72 x 10<sup>-6</sup> A.K<sup>-2</sup>.cm<sup>-2</sup> for W and 5.41 A.K<sup>-2</sup>.cm<sup>-2</sup> for Ni – both deposited via EBD; 2.63 x 10<sup>-3</sup> A.K<sup>-2</sup>.cm<sup>-2</sup> for Ni deposited resistively, and lastly 6.31 x 10<sup>-12</sup> A.K<sup>-2</sup>.cm<sup>-2</sup> for sputtered W. It was concluded that <i>A<sup>*</sup></i> is dependent on the metal contact as well as the type of deposition technique utilized for the Schottky metal contacts.
Supervisor: Mr. PJ Janse van Rensburg E-mail: firstname.lastname@example.org Institution: University of Pretoria