US 2011/0212603 A1 · METHODS FOR IMPROVING THE QUALITY OF STRUCTURES COMPRISING SEMICONDUCTOR MATERIALS

Abstract

Methods which can be applied during the epitaxial growth of semiconductor structures and layers of III-nitride materials so that the qualities of successive layers are successively improved. An intermediate epitaxial layer is grown on an initial surface so that growth pits form at surface dislocations present in the initial surface. A following layer is then grown on the intermediate layer according to the known phenomena of epitaxial lateral overgrowth so it extends laterally and encloses at least the agglomerations of intersecting growth pits. Preferably, prior to growing the following layer, a discontinuous film of a dielectric material is deposited so that the dielectric material deposits discontinuously so as to reduce the number of dislocations in the laterally growing material. The methods of the invention can be performed multiple times to the same structure. Also, semiconductor structures fabricated by these methods.

Claims17

Dependent claims

A method of fabricating a semiconductor structure having a reduced number of surface dislocations comprising:

enhancing the extent of surface disturbance about a plurality of emergent surface dislocations appearing at a semiconductor surface by:
etching the semiconductor surface under first etch conditions selected to encourage etching associated with the surface dislocations;
and
forming an intermediate semiconductor layer under first epitaxial growth conditions selected to encourage opening of growth pits associated with the etched surface dislocations;
depositing a layer of a dielectric masking material so as to cover in a discontinuous manner, at least, the disturbed portions of the surface about a plurality of emergent surface dislocations, portions of the surface being covered with masking material while other portions of the surface not being so covered, and
forming a following semiconductor layer with substantially continuous lateral extent and a reduced number of surface dislocations.

3 more elements

A method for forming a III-nitride semiconductor structure, the semiconductor structure comprising an initial III-nitride surface having a plurality of emergent dislocations, the method comprising exposing the initial surface to a sequence of epitaxial growth conditions selected so as to encourage:

opening of growth pits in an intermediate III-nitride layer growing on the initial surface, the growth pits being associated with the surface dislocations in the initial III-nitride surface and wherein the pits are formed by etching the III-nitride surface under first etch conditions selected to encourage etching associated with the surface dislocations;
intersection of two or more of the growth pits opened in the growing intermediate layer into agglomerations of growth pits;
and
lateral growth of a following III-nitride layer to enclose some or all of the growth pits and the agglomerations of growth pits, wherein the lateral growth continues at least until the following layer has substantially continuous lateral extent, wherein the following layer is formed with a dislocation density that is less than that of the initial surface, and wherein the lateral growth nucleates from portions of growth pits, and agglomerations of growth pits, not covered by a discontinuous layer of a dielectric masking material.

1 more element

Dependencies are inferred from the claim text.

Methods for improving the quality of structures comprising semiconductor materials

Life of this patent

Methods for improving the quality of structures comprising semiconductor materials

Life of this patent

Abstract

Claims17