Method and system for making cobalt silicide

A method of forming silicide materials on a silicon based substrate comprising the steps of:

• (a) depositing a first metal layer on at least selected portions of the silicon based substrate within a first processing chamber of a semiconductor process cluster tool, said first metal layer including an alloy of Cobalt and a refractory metal;
• and wherein said alloy includes a percentage of refractory metal in the range of 1 to approximately 10 percent;
• (b) performing a first heat treatment within the semiconductor process cluster tool so as to convert at least part of said first metal layer and the silicon based substrate into a first silicide composition having one or more cobalt silicide phases, said one or more cobalt silicide phases being characterized by a first resistitivity;
• (c) performing a purge treatment within the semiconductor process cluster tool using a noble gas so as to remove contaminants and reactive gasses at least prior to steps (a) and/or (b);
• (d) performing a second heat treatment so as to convert said first composition, including said one or more cobalt silicide phases, into a second silicide composition containing primarily a lower resistivity cobalt silicide phase, said lower resistivity cobalt silicide phase having a resistivity substantially less than said first resistivity.

A method of forming silicide materials on a silicon based substrate comprising the steps of:

• (a) depositing a first metal layer on the silicon based substrate, said first metal layer including including an alloy of Cobalt and a refractory metal;
• and
• (b) depositing a second metal layer on the silicon based substrate, said second metal layer including a concentration of Cobalt exceeding that of said first metal layer;
• and
• (c) performing a first heat treatment substantially contemporaneously with step (b) so as to convert at least part of said first metal layer, said second metal layer and the silicon based substrate into a first silicide composition having one or more cobalt silicide phases, said one or more cobalt silicide phases being characterized by a first resistitivity;
• and
• (d) performing a second heat treatment so as to convert said first composition, including said one or more cobalt silicide phases, into a second silicide composition containing primarily a lower resistivity cobalt silicide phase, said lower resistivity cobalt silicide phase having a resistivity substantially less than said first resistivity.

A method of forming cobalt salicide on a silicon based wafer, comprising the steps of

• (a) cleaning the silicon based wafer to remove any native oxides and/or contaminants;
• and
• (b) out-gassing the silicon based wafer;
• and
• wherein the silicon based wafer is substantially water-mark free after steps (a) and (b);
• (c) sputtering a first metal layer on the silicon based wafer using an alloy target comprising cobalt (Co) and at least one refractory metal;
• and
• (d) annealing the silicon based wafer in a first anneal treatment to cause said cobalt to react with silicon located on the silicon based wafer;
• wherein steps (b) through (e) are performed in a single semiconductor wafer processing cluster tool.

A cluster tool for performing semiconductor processing operations on a wafer, the cluster tool comprising:

• (a) a load lock chamber for receiving the wafer;
• and
• (b) a sputter chamber equipped with a cobalt alloy target for sputtering a target material on the wafer;
• (c) a heat annealing apparatus for heating the wafer at a rate and temperature sufficient to cause a silicide reaction between the sputtered target material and the wafer.

A semiconductor device comprising:

• a field effect transistor, including at least one source/drain region;
• and
• a silicide contact region connected to said source/drain region;
• and
• said silicide contact region being formed of cobalt-silicide, and further including a trace concentration of a refractory metal.