A process for forming a barrier metal layer and a metal layer on the surface of a contact hole formed on a semiconductor substrate. A titanium and a first titanium nitride layers are sequentially deposited on the surface of the contact hole and annealed, and thereafter, a second titanium nitride layer is deposited on the first titanium nitride layer and annealed, to thereby form a barrier metal layer. A first aluminum layer alloyed with silicon and copper of a given quantity, and a second aluminum layer alloyed with copper of a given quantity, are sequentially deposited on the barrier metal layer, and thereafter performed, the annealing process is performed. A third aluminum layer alloyed with copper of a given quantity is deposited on the second aluminum layer and annealed, to thereby form a metal layer. Accordingly, a leakage current is considerably reduced due to preventions of a silicon extraction phenomenon and an aluminum spike phenomenon, and a contact resistance is reduced and a step coverage is improved by effectively burying the contact hole through the above process, to thereby obtain a reliable semiconductor device.