AVS 51st International Symposium
    Electronic Materials and Processing Tuesday Sessions
       Session EM-TuA

Paper EM-TuA5
Spectroscopic Investigation of Epitaxial Dielectrics on SiC

Tuesday, November 16, 2004, 2:40 pm, Room 304B

Session: Defects and Interfaces in Electronic Materials and Devices
Presenter: J. Choi, University of California, Los Angeles
Authors: J. Choi, University of California, Los Angeles
C.M. Tanner, University of California, Los Angeles
R. Puthenkovilakam, University of California, Los Angeles
J.P. Chang, University of California, Los Angeles
Correspondent: Click to Email
SiC has attracted much attention as a promising wide-bandgap semiconductor material due to its excellent physical and electrical properties. Among other SiC- based devices, group-III nitrides on SiC have demonstrated great device performance as blue light-emitting diodes and high electron mobility transistors. In these devises, inclusion of an AlN buffer layer improves the performance due to its good lattice match with SiC substrate and relatively low misfit with the III-nitride layers. In this work, we demonstrate the deposition of HfO@sub 2@, a well known high-k gate dielectric material for silicon based devices, by an atomic layer deposition process on AlN/SiC. During the thin-film growth, the crystallinity of the epitaxial layers is monitored by in-situ reflection high-energy electron diffraction (RHEED) and the thin film composition is characterized by in-situ x-ray photoelectron spectroscopy (XPS). To examine the characteristic electrical properties, capacitance-voltage and current-voltage measurements are performed on HfO@sub 2@/AlN/SiC and HfO@sub 2@/SiC capacitors fabricated by photolithographic patterning of metal electrodes. The correlation between growth conditions, stoichiometry and crystallinity of the eptaxial layer, and device performance will be discussed. Finally, we present first-principle calculations of the valence band structures of AlN and SiC as well as band alignment at the interface, in comparison with the experimentally determined band alignment by XPS. The experimental band offset is determined by measuring the core-level to valence-band maximum binding energy difference for AlN and SiC at an interface, subsequently scaling them with respect to core-level separation between bulk Si and Al, and agrees well with the theoretical prediction.