I n s i t u cleaning of silicon substrate surfaces by remote plasma-excited hydrogen

Abstract

We have demonstrated a low-temperature cleaning technique for removing both carbon and oxygen from a Si surface. It uses a combination of ex situ wet chemical clean and an in situ remote rf plasma-excited hydrogen clean in an ultrahigh vacuum chamber. Since a remote rf plasma is used, there is insignificant plasma damage or other deleterious effects on surface morphology. A combination of in situ Auger and RHEED analysis has been used to confirm the removal of surface contaminants and the reconstruction of the Si surface. From mass spectroscopy studies, we believe that the hydrogen cleaning is due to a chemical etching of the Si by atomic hydrogen produced by the plasma. This clean is compatible with UHV processing and yields Si substrates that can be used for successful very low temperature (220–400 °C) Si homoepitaxy by remote plasma-enhanced chemical vapor deposition.

Evolution of hydrocarbon species on a silicon surface during methane plasma investigated by in-situ infrared spectroscopy

“…The reference spectrum of the C -H stretching vibration region was recorded after hydrogen plasma treatment. The hydrogen plasma treatment of Si surfaces can considerably reduce the level of contaminant species such as oxygen and hydrocarbons [19,20]. Substrate temperatures were monitored by a chromel -alumel thermocouple that was attached to the Si surface, though the substrate temperature was not controlled.…”

Global model analysis of negative ion generation in low-pressure inductively coupled hydrogen plasmas with bi-Maxwellian electron energy distributions

“…[1][2][3][4] The RF negative ion source is an important application of the hydrogen (or deuterium) plasmas for the neutral beam injection (NBI) systems that heat the plasma and drive plasma currents in fusion reactors. 4 To fulfill the requirement of the international thermonuclear experimental reactor (ITER) negative NBI ion source, the pressure in the source should be low (less than 0.3 Pa) enough to minimize the stripping losses of negative ions in the extraction system.…”

The role of atomic hydrogen in pre-epitaxial silicon substrate cleaning

“…There has also been research in cleaning Si substrates with www.elsevier.com/locate/apsusc Applied Surface Science 253 (2007) 8389-8393 atomic hydrogen obtained from a plasma source at our institute [8][9][10], as well as from other groups, for instance, refs. [11,12].…”