Method for the formation of tin barrier layer with preferential (111) crystallographic orientation

A process for forming, over a silicon surface, a titanium nitride barrier layer having a surface of (111) crystallographic orientation which comprises:

• a) depositing from about 50 to about 1000 Angstroms of a first titanium layer over a silicon surface;
• b) sputtering from about 700 to about 1000 Angstroms of an intermediate titanium nitride layer over said first titanium layer;
• c) depositing from about 300 to about 400 Angstroms of a second titanium layer over said intermediate titanium nitride layer;
• and
• d) annealing the structure in the presence of a nitrogen-bearing gas, and in the absence of an oxygen-bearing gas to form titanium silicide from said first titanium layer over said silicon surface and to form titanium nitride having a surface of (111) crystallographic orientation from said second titanium layer;
• whereby said resulting titanium nitride barrier layer, comprising said sputtered titanium nitride intermediate layer and said titanium nitride formed by annealing said second titanium layer in an atmosphere of nitrogen, has a surface of (111) crystallographic orientation and a sufficient thickness to provide protection of the underlying silicon against spiking by aluminum subsequently formed over said titanium nitride barrier layer.

A process for forming, over a silicon surface, a titanium nitride barrier layer having a surface of (111) crystallographic orientation which comprises:

• a) depositing from about 50 to about 1000 Angstroms of a first titanium layer over a silicon surface;
• b) sputtering from about 700 to about 1000 Angstroms of an intermediate titanium nitride layer over said first titanium layer;
• c) depositing from about 300 to about 400 Angstroms of a second titanium layer over said intermediate titanium nitride layer;
• d) annealing the structure in the presence of a nitrogen-bearing gas, and in the absence of an oxygen-bearing gas in an annealing chamber maintained at a pressure of from about 100 milliTorr to about 800 Torr to form titanium silicide from said first titanium layer over said silicon surface and to form titanium nitride having a surface of (111) crystallographic orientation from said second titanium layer by:
• i) heating said structure up to an annealing temperature ranging from said about 600.degree. C. to about 695.degree. C. at a rate of from about 5.degree. C. per second to about 150.degree. C. per second;
• ii) maintaining said structure at said temperature for a period ranging from about 50 to about 180 seconds;
• iii) raising said annealing temperature up to from about 800.degree. C. to about 900.degree. C. after said initial anneal;
• and
• iv) maintaining said structure at said temperature for an additional time period of from about 5 to about 180 seconds to convert the less stable titanium silicide formed in said first annealing step to a more stable phase;
• whereby said resulting titanium nitride barrier layer, comprising said intermediate sputtered titanium nitride layer and said titanium nitride formed by annealing said second titanium layer in an atmosphere of nitrogen, has a surface of (111) crystallographic orientation and a sufficient thickness to provide protection of the underlying silicon against spiking by aluminum subsequently formed over said titanium nitride barrier layer;
• and
• e) forming an aluminum layer over said (111) oriented titanium nitride surface, whereby said aluminum layer will assume the (111) crystallographic orientation of said titanium nitride surface thereunder, resulting in an aluminum layer having enhanced resistance to electromigration.