Surface morphology and structure of hydrogen etched 3C-SiC(001) on Si(001)
- PDF / 973,227 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 98 Downloads / 212 Views
0911-B08-02
Surface morphology and structure of hydrogen etched 3C-SiC(001) on Si(001) Camilla Coletti1, Martin Hetzel2, Chariya Virojanadara2, Ulrich Starke2, and Stephen E. Saddow1 1 Electrical Engineering, University of South Florida, 4202 E. Fowler Ave., Tampa, FL, 33620 2 Max-Planck-Institut fuer Festkoerperforschung, Heisenbergstr. 1, Stuttgart, Germany
ABSTRACT The surface of 3C-SiC(001) single-crystal epilayers grown on Si(001) substrates is well known to be inhomogeneous and defective. Therefore, the control and understanding at the atomic scale of 3C-SiC surfaces is a key issue. We study the effect of hydrogen etching at different temperatures on the morphology of 3C-SiC(001) surfaces by using atomic force microscopy (AFM) and scanning electron microscopy (SEM). As-grown 3C-SiC(001) samples have been hydrogen etched in a horizontal hot-wall chemical vapor deposition (CVD) reactor at atmospheric pressure for different times and temperatures. Flat, high-quality surfaces presenting defined atomic terraces were observed within the 3C-SiC grain boundaries after etching at 1200°C for 30 minutes. Higher etching temperatures resulted in surfaces with step bunching and enlarged surface defects. Samples etched under the best conditions have been studied using lowenergy electron diffraction (LEED) and Auger electron spectroscopy (AES). INTRODUCTION Single crystal silicon carbide (SiC) is a good candidate for high-power, high-frequency and high–temperature applications. Among the different polytypes, the cubic one (3C-SiC) presents some important material advantages such as a higher carrier mobility which could yield superior high-frequency devices. However, the lack of sufficiently large high-quality 3C-SiC substrates has led to a delay in the development of growth techniques for this polytype and to the introduction of silicon as a large-area substrate material for heteroepitaxial growth. Recently, encouraging results have been reported in the literature showing an improved morphological and crystallographic quality of 3C-SiC [1]. Therefore, the production, understanding, and control of high-quality 3C-SiC surfaces represent the next steps towards improved 3C-SiC electronic devices. Hydrogen etching is well known to improve the quality of commercial mechanically polished SiC wafers for the hexagonal polytypes and to produce highly ordered, passivated surfaces particularly suitable for surface structure studies [2]. In this work, we study the effect of hydrogen etching at different temperatures on the morphology of 3C-SiC samples. We also present preliminary results of surface structure studies conducted in an ultra-high vacuum (UHV) analytical chamber for samples etched under the optimal conditions.
EXPERIMENTAL
The 3C-SiC(001) samples used in this work were grown on Si(001) substrates in a hot wall chemical vapor deposition (CVD) reactor [3]. The quality of as-grown samples before hydrogen etching was studied using atomic force microscopy (AFM). Only samples presenting similar morphological characteristics wer
Data Loading...
