Semiconductor-on-insulator silicon wafer
A method of fabricating a semiconductor-on-insulator semiconductor wafer is described that includes providing first and second semiconductor substrates. A first insulating layer is formed on the first substrate with a first predetermined stress and a second insulating layer is formed on the second substrate with a second predetermined stress different than the first predetermined stress. The first insulating layer is bonded to the second insulating layer to form a composite insulating layer bonding the first substrate to the second substrate and a portion of the one substrate is removed to form a thin crystalline active layer on the composite insulating layer. The first and second insulating layers are formed with different stresses to provide a desired composite stress, which can be any stress from compressive to unstressed to tensile, depending upon the desired application.
1. A semiconductor-on-insulator semiconductor wafer comprising:
a first semiconductor substrate;
a first insulating layer including a first material selected from a group consisting of SiO 2 , Si 3 N 4 , poly Si, and combinations thereof on a surface of the first semiconductor substrate, the first insulating layer having a first predetermined stress;
a second semiconductor substrate;
a second layer including a first material selected from a group consisting of TiSi 2 , CoSi 2 , TaSi 2 , rare earth oxides, rare earth nitrides, rare earth phosphides, rare earth silicides, and combinations thereof on a surface of the second semiconductor substrate, the second layer having a second predetermined stress different than the first predetermined stress;
the first insulating layer being bonded to the second layer to form a composite insulating layer bonding the first semiconductor substrate to the second semiconductor substrate; and
a portion of one of the first semiconductor substrate and the second semiconductor substrate being removed to form a thin crystalline active layer on the composite insulating layer.
2. A semiconductor-on-insulator semiconductor wafer as claimed in claim 1 wherein the first semiconductor substrate includes crystalline silicon and the second semiconductor substrate includes one of crystalline silicon and crystalline germanium.
3. A semiconductor-on-insulator semiconductor wafer as claimed in claim 2 wherein the first insulating layer includes SiO 2 .
4. A semiconductor-on-insulator semiconductor wafer as claimed in claim 1 wherein the second semiconductor substrate includes a high quality silicon substrate and the first semiconductor substrate includes a lower quality silicon substrate and the second semiconductor substrate is removed to form the thin crystalline active layer on the composite insulating layer.
5. A semiconductor-on-insulator semiconductor wafer as claimed in claim 1 wherein the first predetermined stress of the first insulating layer includes compressive stress and the second predetermined stress of the second layer includes tensile stress approximately equal to the compressive stress in the first insulating layer.