Ij. Raaijmakers, LOW-TEMPERATURE METAL-ORGANIC CHEMICAL-VAPOR-DEPOSITION OF ADVANCED BARRIER LAYERS FOR THE MICROELECTRONICS INDUSTRY, Thin solid films, 247(1), 1994, pp. 85-93
Metal-organic chemical vapor deposition (MOCVD) of TiN thin films at l
ow temperatures and low pressures using tetrakis(diethylamino)Ti (TDEA
T) and NH3 is described. Conformal TN films, having layer resistivitie
s of less than 200 muOMEGA cm, densities close to those in sputtered f
ilms and low impurity contents can be obtained with this chemistry. Th
ese TiN films can be applied as adhesion layers for chemically vapor-d
eposited W, or as barrier layers between Si and Al. Many papers descri
be deposition of TiN using tetrakis(dimethylamino)Ti (TDMAT) and NH3 t
o form TiN, presumably because of the conveniently higher vapor pressu
re of TDMAT compared with TDEAT. A direct liquid injection system is u
sed here to enable reproducible introduction of both amines in the rea
ctor. A direct comparison between the TDMAT-NH3 and TDEAT-NH3 chemistr
ies and the properties of the resulting films is made. It is found tha
t the more reactive TDMAT-NH3 chemistry produces non-conformal films h
aving a higher resistivity (> 1200 muOMEGA cm) and lower density. Fina
lly, MOCVD of advanced amorphous barrier materials, comprising a terna
ry Ti-Si-N alloy, is described. Such amorphous ternary barriers are ca
ndidates for application in future Cu metallization schemes.