FinFet with heterojunction and improved channel control

A method of making a first transistor and a second transistor, the method comprising:

• epitaxially forming a first region and a second region above a common buffer layer, the first region formed of a first crystalline semiconductor material, the second region formed of a second crystalline semiconductor material different from the first semiconductor material, and the common buffer layer formed of a third crystalline semiconductor material;
• forming a first fin from the first region, the first fin including a first channel region of the first transistor between a source region of the first transistor and a drain region of the first transistor, the first fin on a first fin support;
• forming the first fin support from the common buffer layer, the first crystalline semiconductor material of the first fin and the third crystalline semiconductor material of the first fin support forming a first heterojunction in between;
• forming a second fin from the second region, the second fin including a second channel region of the second transistor between a source region of the second transistor and a drain region of the second transistor, the second fin on a second fin support;
• and
• forming the second fin support from the common buffer layer, the second crystalline semiconductor material of the second fin and the third crystalline semiconductor material of the second fin support forming a second heterojunction in between.