Low temperature rapid thermal low pressure chemical vapor deposition of 〈111〉 oriented TiN layers from the TiCl 4NH 3H 2 gaseous phase

Abstract

Titanium nitride layers are deposited by Rapid Thermal Low-Pressure Chemical Vapor Deposition (RTLPCVD) from the TiCl 4NH 3H 2 gaseous phase. Growth rate, resistivity and crystallographic orientation are studied as a function of the deposition temperature and the NH 3/TiCl 4 partial pressures ratio called R. To fulfill the TiN barrier layer requirements, the deposition temperature and the R value have to be as low as possible. We show that with such conditions, the preferential orientation of the deposited TiN layer is always 〈200〉. This orientation enhances the 〈200〉 orientation of the aluminium overlayer which leads to poor electromigration resistance. In order to obtain 〈111〉 oriented TiN layer, a two step process is proposed. In this way, 〈111〉 oriented TiN layers are deposited at a deposition temperature and with an R ratio value as low as 500°C and 4, respectively. The resistivity of such as-deposited films is 200 μΩcm.