Formation of boride barrier layers using chemisorption techniques

Abstract

In one embodiment, a method for depositing a boride-containing barrier layer on a substrate is provided which includes exposing the substrate sequentially to a boron-containing compound and a tungsten precursor to form a first boride-containing layer during a first sequential chemisorption process, and exposing the substrate to the boron-containing compound, the tungsten precursor, and ammonia to form a second boride-containing layer over the first boride-containing layer during a second sequential chemisorption process. In one example, the tungsten precursor contains tungsten hexafluoride and the boron-containing compound contains diborane. In another embodiment, a contact layer is deposited over the second boride-containing layer. The contact layer may contain tungsten and be deposited by a chemical vapor deposition process. Alternatively, the contact layer may contain copper and be deposited by a physical vapor deposition process. In other examples, boride-containing layers may be formed at a temperature of less than about 500° C.