Very High Frequency Plasma Enhanced Chemical Vapor Deposition Research Articles

Very High Frequency Plasma Enhanced Chemical Vapor Deposition of TiSix/TiN1-xSix Barrier Films

Very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD) of titaniumsilicide /titaniumnitride barrier films using the silane reduction process with a TiCl4 source is described. VHF plasma, which is denser than a conventional RF plasma, produces a large number of excited species. The silane reduction process, which supplies excited species such as SiHx radicals and SiHx + ions as reductants in plasma, promotes dissociation of TiCl4 precursors more than a conventional hydrogen reduction process. Therefore, the VHF-PECVD with the silane reduction process forms high quality titaniumsilicide/titaniumnitride barrier films, which have a low Cl content (<0.2 at.%). In the silane reduction process, the Ti–Si bond is simultaneously formed into the bond structure, resulting in depositing Si-containing films of TiSix or TiN1-x Six . The resistivity of TiSix or TiN1-x Six is about 100 µ Ω· cm. The surface morphology of TiSix films is very smooth and the structure of TiN1-x Six films is amorphous.

Selective deposition of polycrystalline silicon thin films at low temperature by hot-wire chemical vapor deposition

Polycrystalline silicon thin films have been selectively deposited at a substrate temperature of 300 °C on molybdenum or silicon over silicon dioxide, silicon nitride or Corning 7059 glass substrates in a continuous hot-wire chemical vapor deposition (HWCVD) process involving hydrogen and disilane. Excellent selectivity is achieved on features as small as 1 μm spaced molybdenum lines. The deposition rate on molybdenum is 60–100 Å/min which is higher than that obtained by a pulsed gas plasma-enhanced chemical vapor deposition (PECVD) or a very high-frequency PECVD (VHF-PECVD). The selective deposition rate obtained in our system is attributed to the high concentration of atomic hydrogen generated when molecular hydrogen passes over a heated tungsten filament.