This composite substrate has a single-crystal semiconductor thin film (13) provided to at least the front surface of an inorganic insulating sintered-body substrate (11) having a thermal conductivity of at least 5 W/m.Math.K and a volume resistivity of at least 110.sup.8 .Math.cm. The composite substrate also has, provided between the inorganic insulating sintered-body substrate (11) and the single-crystal semiconductor thin film (13), a silicon coating layer (12) comprising polycrystalline silicon or amorphous silicon.

As a result of the present invention, metal impurity contamination from the sintered body can be inhibited, even in a composite substrate in which a single-crystal silicon thin film is provided upon an inexpensive ceramic sintered body which is opaque with respect to visible light, which exhibits an excellent thermal conductivity, and which further exhibits little loss at a high frequency range, and characteristics can be improved.

A method of manufacturing a semiconductor device includes forming a dummy gate structure over a substrate. The dummy gate structure has a dummy gate dielectric layer and a dummy gate electrode layer. Sidewall spacers including one or more layers of insulating materials are formed on sidewalls of the dummy gate structure. A silicon based liner is formed over the sidewall spacers. A first insulating layer is formed over the silicon based liner. The silicon based liner and the first insulating layer are thermally treating causing a reduction in a volume of the first insulating layer and an increase in a volume of the silicon based liner. The dummy gate structure is removed to form a gate space in the first insulating layer. The gate space is formed with a high-k dielectric layer and a first conductive layer.

A cost effective process flow for manufacturing semiconductor on insulator structures is parallel is provided. Each of the multiple semiconductor-on-insulator composite structures prepared in parallel comprises a charge trapping layer (CTL).

A method of manufacturing a semiconductor device includes forming a dummy gate structure over a substrate. The dummy gate structure has a dummy gate dielectric layer and a dummy gate electrode layer. Sidewall spacers including one or more layers of insulating materials are formed on sidewalls of the dummy gate structure. A silicon based liner is formed over the sidewall spacers. A first insulating layer is formed over the silicon based liner. The silicon based liner and the first insulating layer are thermally treating causing a reduction in a volume of the first insulating layer and an increase in a volume of the silicon based liner. The dummy gate structure is removed to form a gate space in the first insulating layer. The gate space is formed with a high-k dielectric layer and a first conductive layer.