Method for the formation of fin structures for FinFET devices

A method for fabricating a fin of a FinFET transistor supported by a substrate formed of a first semiconductor material, comprising:

• depositing a sacrificial layer formed of a second semiconductor material on the substrate;
• forming an additional layer of a third semiconductor material over the sacrificial layer;
• patterning the sacrificial layer and additional layer to define a fin;
• covering the fin with a cap and sidewall spacer;
• selectively removing the second semiconductor material of the sacrificial layer to form an opening below the fin so that the fin is supported by said sidewall spacer;
• and
• filling the opening with a dielectric material so as to form an insulating pedestal which isolates any semiconductor materials of the fin from the substrate.

A method for fabricating a fin of a FinFET transistor supported by a substrate formed of a first semiconductor material, comprising:

• depositing a sacrificial layer formed of a second semiconductor material on the substrate;
• forming an intermediate layer of a third semiconductor material over the sacrificial layer;
• forming an upper layer of a fourth semiconductor material over the intermediate layer;
• patterning the sacrificial, intermediate and upper layers to define a fin including a first region made from the sacrificial layer, a second region made from the intermediate layer and a third region made from the upper layer;
• covering the fin with a cap and sidewall spacer;
• selectively removing the first region by selectively etching the second semiconductor material to form an opening below the second region in each fin leaving portions of the sidewall spacer to support the fin;
• and
• filling the opening with a dielectric material so as to form an insulating pedestal which isolates the second and third regions of the fin from the substrate.