High mobility transistors

A method of forming an integrated circuit, comprising the steps:

• providing a substrate comprising silicon, said substrate having a first region of a first conductivity type in an area for a first polarity finFET and having a second region of a second, opposite, conductivity type in an area for a second, opposite, polarity finFET;
• forming a dielectric layer over said substrate;
• concurrently forming a first trench in said dielectric layer down to said substrate in said area for said first polarity finFET and a second trench in said dielectric layer down to said substrate in said area for said second polarity finFET;
• concurrently forming a first silicon germanium buffer on said substrate in said first trench and a second silicon germanium buffer on said substrate in said second trench;
• concurrently forming a first polarity fin of said first polarity finFET on said first silicon germanium buffer and a second polarity fin of said second polarity finFET on said second silicon germanium buffer, so that said first polarity fin and said second polarity fin extend above a top surface of said dielectric layer;
• forming a cap layer of dielectric material over said dielectric layer so as to cover said first polarity fin and said second polarity fin;
• removing said cap layer by a CMP process so as to planarize said first polarity fin and said second polarity fin down to said dielectric layer;
• and
• recessing said dielectric layer so that said first polarity fin and said second polarity fin extend at least 10 nanometers above said dielectric layer.