Abstract:
For manufacturing an SOI substrate, the following steps are carried out: providing a wafer of semiconductor material; forming, inside the wafer, a plurality of passages forming a labyrinthine cavity and laterally delimiting a plurality of pillars of semiconductor material; and oxidizing the pillars of semiconductor material to form a buried insulating layer. For forming the labyrinthine cavity, a trench is first formed in a substrate; an epitaxial layer is grown, which closes the trench at the top; the wafer is annealed so as to deform the pillars and cause them to assume a minimum-energy handlebar-like shape, and a peripheral portion of the wafer is removed to reach the labyrinthine cavity, and side inlet openings are formed in the labyrinthine cavity. Oxidation is performed by feeding an oxidizing fluid through the side inlet openings.
Abstract:
The process comprises the steps of forming, on top of a semiconductor material wafer, a holed mask having a lattice structure and comprising a plurality of openings each having a substantially square shape and a side with an inclination of 45null with respect to the flat of the wafer; carrying out an anisotropic etch in TMAH of the wafer, using said holed mask, thus forming a cavity, the cross section of which has the shape of an upside-down isosceles trapezium; and carrying out a chemical vapor deposition using TEOS, thus forming a TEOS layer which completely closes the openings of the holed mask and defines a diaphragm overlying the cavity and on which a suspended integrated structure can subsequently be manufactured.