AVS 51st International Symposium
    Thin Films Monday Sessions
       Session TF-MoP

Paper TF-MoP24
In-situ Characterization of HfO@sub 2@ and AlN Films on SiC

Monday, November 15, 2004, 5:00 pm, Room Exhibit Hall B

Session: Poster Session
Presenter: C.M. Tanner, University of California, Los Angeles
Authors: C.M. Tanner, University of California, Los Angeles
J. Choi, University of California, Los Angeles
J.P. Chang, University of California, Los Angeles
Correspondent: Click to Email
High dielectric constant materials are promising gate oxide materials for future generations of metal-oxide-semiconductor field effect transistor (MOSFETs). HfO@sub 2@ has a high dielectric constant and excellent thermal stability, indicating its suitability for high-power and high-temperature applications, especially when wide band gap semiconductors such as SiC are used as the substrate. Due to its close lattice matching with SiC, AlN is generally grown as a single crystalline layer on SiC and may provide an effective buffer layer between SiC and HfO@sub 2@. In addition, the AlN/SiC band offsets are quite symmetric, providing the needed barrier heights for an effective device operation. In this work, HfO@sub 2@ and AlN films were synthesized using atomic layer deposition (ALD) under high-vacuum conditions. Stacked HfO@sub 2@/AlN films were also grown on SiC in addition to the individual dielectric layers on SiC. The substrate temperature was controlled by infrared heating with a quartz tungsten halogen lamp. Hafnium tetra-tert-butoxide and oxygen were used to deposit HfO@sub 2@, while trimethylaluminum and ammonia were used to deposit AlN. Alternating pulses of chemicals were sequentially introduced into the reactor while film growth was monitored by in-situ reflection high-energy electron diffraction (RHEED) to study the surface structure. In-situ X-ray photoelectron spectroscopy (XPS) was used to study film composition and chemical bonding at the interface. The deposition kinetics of HfO@sub 2@ and AlN films were studied at various substrate temperatures and precursor doses. Film thickness and uniformity were determined by spectroscopic ellipsometry and confirmed with XPS. The microstructure of the interfaces of HfO@sub 2@/AlN/SiC stacked films was characterized using transmission electron microscopy (TEM).