Patent ID: 8846493
Filing Date: 2014-09-30
Classification: H01L

Abstract:
1. A method for preparing a silicon-on-insulator structure comprising a handle wafer, a silicon device layer, a dielectric layer between the handle wafer and the silicon device layer, the handle wafer having an axis, a radius, a front surface, a back surface, and a peripheral edge extending in the axial direction from the front surface to the back surface, wherein the front surface of the handle wafer forms an interface with the dielectric layer, with the handle-dielectric interface and back surface being perpendicular to the axis, and wherein the handle wafer further comprises a surface layer extending in the axial direction from the handle-dielectric interface towards the back surface to a depth, D sl which comprises a high resistivity region and a bulk layer extending from the surface layer towards the back surface, the handle wafer having a resistivity profile in which a peak resistivity R peak exists in the high-resistivity region, the resistivity generally decreasing from the peak resistivity towards the bulk layer, the method comprising: selecting a handle wafer with a given dopant concentration and interstitial oxygen concentration, the handle wafer being doped with a dopant of a first type, the dopant of the first type being either a p-type or n-type dopant; forming a high resistivity region in the surface layer of the handle wafer by forming a dielectric layer on at least one surface of the donor wafer and/or the front surface of the handle wafer; bonding a donor wafer and the handle wafer to form a bonded wafer wherein the donor wafer and handle wafer are separated along the axis by the dielectric layer, the dielectric layer forming a donor-dielectric interface between the donor wafer and dielectric layer and a handle-dielectric interface between the dielectric layer and front surface of the handle wafer, the bonded wafer comprising a bond interface located at the donor-dielectric interface, the handle-dielectric interface or in the dielectric layer between the two interfaces; and removing a portion of the donor wafer from the bonded wafer such that a silicon layer remains bonded to the dielectric layer to form the silicon on insulator structure.