Method of manufacturing a semiconductor device and a semiconductor device

A semiconductor device, comprising:

• semiconductor wires disposed over a substrate, each of the semiconductor wires having a channel region and a source/drain region;
• a source/drain epitaxial layer wrapping around the source/drain region of each of the first semiconductor wires;
• a gate dielectric layer disposed on and wrapping around the channel region of each of the first semiconductor wires;
• a gate electrode layer disposed on the gate dielectric layer and wrapping around the channel region;
• and
• inner spacers each comprising multiple insulating layers made of different material from each other and disposed in a space which is defined by adjacent first semiconductor wires, the gate dielectric layer and the source/drain region,
• wherein each of the inner spacers has a rectangular cross section.

A semiconductor device, comprising:

• semiconductor wires disposed over a substrate, each of the semiconductor wires having a channel region and a source/drain region;
• a source/drain epitaxial layer disposed on the source/drain region of each of the first semiconductor wires;
• a gate dielectric layer disposed on and wrapping around the channel region of each of the first semiconductor wires;
• a gate electrode layer disposed on the gate dielectric layer and wrapping around the channel region;
• and
• inner spacers each comprising a first insulating layer conformally disposed in a space which is defined by adjacent first semiconductor wires, the gate dielectric layer and the source/drain region,
• wherein each of the inner spacers has a rectangular cross section.