This study demonstrates the cleaning of Si(100) surfaces with a remote H2/SiH4 plasma. The surfaces were prepared with a chemical oxide the remains after an RCA clean. The plasma cleaning process was designed to remove contaminants such as C, F, and SiO2. The key to successful removal of the oxide is to have the plasma chemistry in a neutral deposition regime. The neutral deposition process regime is a balance between the deposition of Si by SiH4 and the etching of the deposited Si by atomic H. During the neutral deposition mode the SiO2 was removed without deposition of Si on the SiO2 surface. Once the SiO2 layer is removed, theunderlying Si surface is exposed to the H2/SiH4 plasma and a thin epitaxial film may be deposited. The final Si surface configuration after plasma cleaning is a 2×1 hydrogen terminated surface. The characterization of the interface and epitaxial film were investigated using Auger electron spectroscopy (AES) and transmission electron microscopy (TEM).

Reactive ion etching of a patterned silicon dioxide layer leaves behind a uniform fluorocarbon layer which must subsequently be removed. Both surface and via polymeric residues form during the reactive ion etch step and their removal using H 2 -based plasma clean processes is reported here. X-ray photoelectron spectroscopy was used to determine the composition of the residue. Scanning electron microscope images were taken before and after the dry clean treatment to determine the effectiveness of the residue removal process. A radio-frequency-generated hydrogen plasma was used in the dry clean experiments. Power, temperature, and pressure were varied while gas flow was kept constant at 75 sccm and the process time was 5-10 min. The surface residue (on the oxide) was most efficiently removed at 400 W, 450°C, and 15 mTorr when exposed to the plasma for 10 min. The in-via residue was best removed following a 5 min plasma exposure at 100 W, 450°C and 15 mTorr.

We have investigated on the effect of different substrate surfaces in changing the microstructure of µc-SixGe1-x:H films prepared by reactive magnetron sputtering. Films were deposited on hydrogen terminated Si(111), Si(100) surfaces, and surfaces chemical and plasma oxides. The thin film microstructure was characterized by Fourier transform infrared spectroscopy (FTIR), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and Raman scattering.

Phase formations in Co thin films (200Å in thickness) reacting with atomically clean Si(100), Ge(100), and Si0.80Ge0.20 epitaxial layer (800Å in thickness on Si(100) substrates) in UHV have been investigated. For the Co/Si system, it is found that CoSi (FeSi structure) is formed at 375°C through a very disordered CoSi phase, and the final CoSi2 phase is formed at 575°C. On the other hand, the CosGe7 phase was identified for the Co/Ge samples annealed at 300°C and 450°C and the final CoGe2 phase is formed at 600°C. For the Co/Si0.8Ge0.20 samples annealed from 400°C to 600°C, Co(Si1-yGey) phases with y-0.10 were detected, and for annealing at 700°C, only the CoSi2 phase was formed. These results indicate a preferential CoSi reaction when annealing the Co/SiGe structure. It was also found that the sheet resistance of the reacted thin films depend strongly on annealing temperature.