The Microstructure of Silicon-on-Insulator Structures Formed by High Dose Oxygen Ion Implantation

ABSTRACTCross-sectional and plan view transmission electron microscopy and high resolution scanning electron microscopy have been used to characterize the microstructure of silicon-on-insulator formed by high dose oxygen ion implantation. The complete microstructure was observed to be composed of a series of distinct zones. The top silicon layer was {100} single crystal with a very low dislocation density. The second layer was a mixture of fine grained polysilicon and amorphous SiO2. The third layer was pure SiO2 , followed by a second mixed layer. Finally, there was a layer of {100} silicon with an extremely high dislocation density. Some of the dislocations extended as far as 1 μm into the Si substrate. The relative widths of the layers were found to depend on the total ion fluence. The oxide layer did not occur for low doses and the two mixed layers merged into one zone. At high doses, the silicon-silicon dioxide interfaces are abrupt due to internal oxidation.