Methods and apparatus for increasing reflectivity of an aluminum layer on a substrate. In some embodiments, a method of depositing an aluminum layer on a substrate comprises depositing a layer of cobalt or cobalt alloy or a layer of titanium or titanium alloy on the substrate with a chemical vapor deposition (CVD) process, pre-treating the layer of cobalt or cobalt alloy with a thermal hydrogen anneal at a temperature of approximately 400 degrees Celsius if a top surface of the layer of cobalt or cobalt alloy is compromised, and depositing a layer of aluminum on the layer of cobalt or cobalt alloy or the layer of titanium or titanium alloy with a CVD process at a temperature of approximately 120 degrees Celsius. Pre-treatment of the layer of cobalt or cobalt alloy may be accomplished for a duration of approximately 60 seconds to approximately 120 seconds.