Method for forming isolated semiconductor structures

A method of forming a dielectrically isolated single crystal semiconductor island in a semiconductor body, comprising the steps of:

• implanting ions of a group Zero element into the body through a surface of the body at an energy and a dose so that a first region inside the body is substantially amorphized while a second region of the body including the surface and extending to the first region is not substantially amorphized;
• forming a first trench in the body from the surface to the first region, the trench being defined at least in part by a first sidewall of the second region;
• subjecting the body to an oxidizing environment to convert at least a portion of the first region to a continuous buried oxide layer, and the first sidewall and surface of the second region to oxide, wherein the dose of said implanting step suppresses complete recrystallization of the first region;
• removing oxide from the surface of the second region remaining after said first trench forming step and said oxidizing environment subjecting step to expose single crystal semiconductor material of the body;
• epitaxially depositing semiconductor material on the exposed single crystal semiconductor material of the body to form an epitaxial layer;
• forming a second trench in the epitaxial semiconductor layer from a surface thereof to the buried oxide layer, the second trench being defined at least in part by a sidewall of the epitaxial layer and a second sidewall of the second region;
• and
• forming a dielectric layer on the sidewall of the epitaxial layer and on the second sidewall of the second region.

A method for forming dielectrically isolated single crystal semiconductor islands in a semiconductor substrate, comprising the steps of:

• implanting ions of a group Zero element into the substrate at an energy and a dose so that an amorphized region is formed within the substrate;
• forming a first trench mask over the substrate, windows thereof being disposed over the amorphized region;
• etching the substrate through the first trench mask at least into proximity with the amorphized region to form single crystal substrate regions separated from one another by trenches and from an underlying region of the substrate by respective sections of the amorphized region.
• oxidizing the amorphized region sections to form dielectric segments underlying the single crystal substrate regions, wherein the dose of the implanted group Zero ion suppresses completed recrystallization of the amorphized region;
• exposing respective upper surfaces of the single crystal substrate regions;
• growing a layer of epitaxial semiconductor material on the upper surfaces of the single crystal substrate regions;
• forming a second trench mask over the epitaxial semiconductor material layer, the epitaxial semiconductor material layer being exposed through the second trench mask in a pattern substantially similar to the pattern of the first trench mask;
• and
• etching the epitaxial semiconductor material through the second trench mask at least into proximity with the dielectric segments to form single crystal islands separated from one another by trenches and from the underlying substrate region by the dielectric segments.