Semiconductor Devices and Methods of Manufacturing the Same

A method of manufacturing a semiconductor device, the method comprising:

• forming a first conductive layer on a substrate;
• and
• forming a second conductive layer on the first conductive layer, wherein the first conductive layer and the second conductive layer form part of a gate electrode,
• wherein an aluminum concentration of the first conductive layer is different from an aluminum concentration of the second conductive layer.

A semiconductor device comprising:

• a gate dielectric pattern on a substrate;
• and
• a gate electrode on the gate dielectric pattern opposite the substrate, wherein the gate electrode comprises:
• a first conductive pattern on the gate dielectric pattern, the first conductive pattern comprising aluminum;
• and
• a second conductive pattern disposed between the first conductive pattern and the gate dielectric pattern, the second conductive pattern comprising aluminum and having an aluminum concentration that is higher than an aluminum concentration of the first conductive pattern.