Completely dielectrically isolated silicon for high voltage application produced by ZMR of poly Si on SiO2

The aim is to demonstrate that it is possible to create completely dielectrically isolated Si using the zone-melted recrystallization (ZMR) technique and that the material quality allows application to high-voltage devices. In the first case the seeding windows were etched into the thermal oxide in the area between the tub-shaped grooves. Polycrystalline silicon films of different thicknesses (up to 80 μm) were deposited. In the second case a thin polycrystalline silicon film (1 μm) acts as a connection between the single-crystalline substrate and poly-Si in the grooves. The seeding recrystallization results in single-crystalline silicon (100)-oriented substrate. A detailed TEM (transmission electron microscopy) characterization demonstrates the good crystalline quality of the SOI films. There are only separated dislocations or small clusters of dislocations in some areas, but this is not a typical result. Typically, there are wide areas free of defects