Titanium Silicide Films Deposited by Low Pressure Chemical Vapor Deposition

Abstract

Smooth titanium silicide films have been deposited using a Low Pressure Chemical Vapor Deposition (LPCVD) process. A system has been designed and built for the LPCVD of titanium silicide. It is a cold wall reactor with the wafer being heated externally by infrared lamps. Sequential deposition of polycrystalline silicon (polysilicon) and titanium silicide films, and in-situ annealing of these films, if required, can be performed in this system. A turbomolecular pump is used to provide a contaminant free environment with a base pressure of <10−7 torr. SiH4 and TiCl4 are used as silicon and titanium sources, respectively.Tithnium silicide films with resistivities ranging from 22 to 39 μΩ-cm have been obtained. At low deposition rates, these films have surface roughnesses ranging from 50 to 250 Å. From X-ray diffractometry, it was determined that the as-deposited titanium silicide films were polycrystalline, and TiSi2 was the predominant phase. Si/Ti ratios of 1.8 to 2.3 were obtained frog Rutherford Backscattering Spectroscopy (RBS). Auger analyses did not show any impurities such as oxygen, carbon or chlorine in these films.

LPCVD of Titanium Disilicide: Selectivity of Growth

“…Chemical vapor deposition, however, is a very attractive alternative (4): (i) low pressure chemical vapor deposition (LPCVD) allows a good uniformity of films in thickness and composition (5,6), and (ii) this method involves surface reaction so selectively deposited films are possible under specific conditions. The possibility of selective deposition of titanium silicide is just mentioned as possible (8,9). The possibility of selective deposition of titanium silicide is just mentioned as possible (8,9).…”

“…Recently, some papers relate the selective deposition of tungsten by LPCVD (7). The possibility of selective deposition of titanium silicide is just mentioned as possible (8,9).…”