Nano-Structured Amporphous Carbon Films Synthesised Using DECR Plasma
Abstract
A Distributed Electron Cyclotron Resonance plasma reactor powered by a microwave generator operating at 2.45 GHz was used to deposit ta-C:H (Diamond-Like Carbon, DLC) thin films at RT. A graphite sputtering target immersed in an argon plasma was used as carbon source. The Ar plasma density was about 5x10A(exp10)cm(exp-3). Single crystal <100> Si substrates were RF biased to a negative voltage of -80 V. Atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), nuclear reaction analysis (NRA) using the resonance at 6.385 MeV of the reaction: (15)N + (1)H-->(12)C + (4)He + gamma, elastic recoil detection analysis (ERDA) and Rutherford backscattering (RBS) were used to investigate the early phase of the growth. The morphology of the films grown at low pressure (0.3 mTorr) is shown to be dominated by stress-mediated nucleation leading to formation of basket-like clusters of circular hillocks 20 nm high surrounded by a planar, mostly sp(exp2) bonded film ^8 nm thick. With increasing plasma pressure the spatial frequency of the hillocks becomes random and the growth is dominated by the Stranski-Krastanov mode. The XPS data taken at decreasing emergence angles show that the structure of the hillocks is dominated by sp(exp3) bonded carbon. The XPS argon signal disappears at 100 emergence angle indicating that integration of argon occurs mainly within the sp(exp2) bonded regions. The NRA and ERDA analysis show that the amount of integrated hydrogen decreases with increasing substrate current density. RIBS data indicate that increasing bias enhances argon integration.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 2001
- Accession Number
- ADP012167
Entities
People
- Andre Golanski
- Dieter Grambole
- Folker Herrmann
- Jean Hommet
- Philippe Kern
Organizations
- Cork Institute of Technology