Structure and method of making double-gated self-aligned finfet having gates of different lengths

A gated semiconductor device, comprising:

• a fin-shaped body having a first dimension extending in a lateral direction parallel to a major surface of a substrate, and second dimension extending in a direction at least substantially vertical and at least substantially perpendicular to the major surface, the body having a first side and a second side opposite the first side;
• a first gate consisting essentially of polycrystalline silicon germanium overlying the first side, the first gate having a first gate length in the lateral direction;
• and
• a second gate consisting essentially of polysilicon overlying the second side, the second gate having a second gate length in the lateral direction which is different from the first gate length, the second gate being electrically isolated from the first gate.

A method of making a gated semiconductor device, comprising:

• patterning a single-crystal semiconductor region of a substrate to extend in a lateral direction parallel to a major surface of a substrate and to extend in a direction at least substantially vertical and at least substantially perpendicular to the major surface, the semiconductor region having a first side and a second side opposite the first side;
• forming a first gate overlying the first side, the first gate having a first gate length in the lateral direction;
• and
• forming a second gate overlying the second side, the second gate having a second gate length in the lateral direction which is different from the first gate length, the second gate being electrically isolated from the first gate.