Semiconductor device

A semiconductor device, comprising:

• a first semiconductor fin extending from a substrate, the first semiconductor fin having a silicon (Si) channel region, the Si channel region is a channel of an n-type transistor;
• a second semiconductor fin extending from the substrate, the second semiconductor fin having a silicon germanium (SiGe) channel region, the SiGe channel region is a channel of a p-type transistor;
• a first gate dielectric contacting the Si channel region and comprising a first hafnium oxide layer wrapping around the Si channel region, and a first yttrium oxide layer disposed above the first hafnium oxide layer, wherein the first yttrium oxide layer is in contact with a top surface and opposite sidewalls of the first hafnium oxide layer to wrap around the first hafnium oxide layer;
• a second gate dielectric contacting the SiGe channel region and comprising a second hafnium oxide layer wrapping around the SiGe channel region, and a second yttrium oxide layer in contact with a top surface and opposite sidewalls of the second hafnium oxide layer to wrap around the second hafnium oxide layer;
• a first metal gate electrode wrapping around and contacting the first gate dielectric;
• and
• a second metal gate electrode wrapping around and contacting the second gate dielectric, wherein the first and second metal gate electrodes have a same work function metal composition, and the first and second gate dielectrics have a same dielectric composition.

A semiconductor device, comprising:

• a silicon (Si) fin protruding from a substrate and having an n-channel region;
• a silicon germanium (SiGe) fin protruding from the substrate and having a p-channel region;
• a first gate dielectric comprising a first hafnium oxide layer extending across the Si fin, and a first strontium oxide layer in contact with a top surface and opposite sidewalls of the first hafnium oxide layer to wrap around the first hafnium oxide layer;
• a second gate dielectric comprising a second hafnium oxide layer extending across the SiGe fin, and a second strontium oxide layer in contact with a top surface and opposite sidewalls of the second hafnium oxide layer to wrap around the second hafnium oxide layer;
• a first work function metal contacting the first strontium oxide layer of the first gate dielectric;
• and
• a second work function metal contacting the second strontium oxide layer of the second gate dielectric, wherein the first and second work function metals have a same metal composition, and the first and second gate dielectrics have a same number of layers.