Patent ID: 9748404
Date: 2017-08-29
CPC Classifications: H01L

Claim:
1. A method for fabricating a semiconductor device, the method comprising: forming a sacrificial layer of a first semiconductor material on a substrate; forming a layer of a second semiconductor material on the sacrificial layer; forming a layer of a third semiconductor material on the layer of the second semiconductor material; removing portions of the layer of the third semiconductor material, portions of the second semiconductor material, and portions of the sacrificial layer to expose portions of the substrate and form a sacrificial fin in the sacrificial layer, a first nanowire arranged on the sacrificial fin and a second nanowire arranged on the first nanowire; depositing a layer of insulator material on the substrate adjacent to the sacrificial fin; etching to remove exposed portions of the first nanowire; and performing an oxidizing process that forms a first layer of oxide material on exposed portions of the second nanowire and a second layer of oxide material on exposed portions of the sacrificial fin, the first layer of oxide material having a first thickness and the second layer of oxide material having a second thickness, where the first thickness is less than the second thickness.