Divot reduction in SIMOX layers
View Patent ↗A method of fabricating a silicon-on-insulator (SOI) having a superficial Si-containing layer that has a reduced number of tile and divot defects is provided. The method includes the steps of: implanting oxygen ions into a surface of a Si-containing substrate, the implanted oxygen ions having a concentration sufficient to form a buried oxide region during a subsequent annealing step; and annealing the substrate containing implanted oxygen ions under conditions wherein the implanted oxygen ions form a buried oxide region which electrically isolates a superficial Si-containing layer from a bottom Si-containing layer. Moreover, the annealing conditions employed are capable of reducing the number of tile or divot defects present in the superficial Si-containing layer so as to allow optical detection of any other defect that has a lower density than the tile or divot defect. The present invention also relates to the SOI substrate that is produced using the inventive method.
1. A silicon-on-insulator (SOI) substrate comprising:
a buried oxide region having a thickness from about 1000 to about 2000 Å that is sandwiched between a superficial Si-containing layer having a thickness from about 100 to about 2000 Å and a bottom Si-containing layer, said superficial Si-containing layer having an upper surface including a number of tile defects or divot defects having a first density that does not obstruct detection of other defects that have a second density that is lower than the first density.
2. The SOI substrate of claim 1 wherein said buried oxide region has a uniform interface with said superficial Si-containing layer.
3. The SOI substrate of claim 1 wherein said buried oxide region has an undulating defect-containing interface with said superficial Si-containing layer.
4. The SOI substrate of claim 1 wherein said superficial Si-containing layer is smooth and has a glass-like appearance.
5. The SOI substrate of claim 1 wherein said buried oxide region is present continuously through the substrate.
6. The SOI substrate of claim 1 wherein said substrate comprises discrete and isolated buried oxide regions.
7. The SOI substrate of claim 6 wherein some of said discrete and isolated buried oxide regions have an undulating defect-containing interface with said superficial Si-containing layer.