Roughly described, a computer program product describes a transistor with a fin, a fin support, a gate, and a gate dielectric. The fin includes a first crystalline semiconductor material which includes a channel region of the transistor between a source region of the first transistor and a drain region of the transistor. The fin is on a fin support. The fin support includes a second crystalline semiconductor material different from the first crystalline semiconductor material. The first crystalline semiconductor material of the fin and the second crystalline semiconductor material of the fin support form a first heterojunction in between. A gate, gate dielectric, and/or isolation dielectric can be positioned to improve control within the channel.