III-N semiconductor heterostructures including a raised III-N semiconductor structures with inclined sidewall facets are described. In embodiments, lateral epitaxial overgrowth favoring semi-polar inclined sidewall facets is employed to bend crystal defects from vertical propagation to horizontal propagation. In embodiments, arbitrarily large merged III-N semiconductor structures having low defect density surfaces may be overgrown from trenches exposing a (100) surface of a silicon substrate. III-N devices, such as III-N transistors, may be further formed on the raised III-N semiconductor structures while silicon-based transistors may be formed in other regions of the silicon substrate.

Techniques are disclosed for forming a GaN transistor on a semiconductor substrate. An insulating layer forms on top of a semiconductor substrate. A trench, filled with a trench material comprising a III-V semiconductor material, forms through the insulating layer and extends into the semiconductor substrate. A channel structure, containing III-V material having a defect density lower than the trench material, forms directly on top of the insulating layer and adjacent to the trench. A source and drain form on opposite sides of the channel structure, and a gate forms on the channel structure. The semiconductor substrate forms a plane upon which both GaN transistors and other transistors can form.

A method for making a semiconductor device may include forming a superlattice on a substrate comprising a plurality of stacked groups of layers, with each group of layers including a plurality of stacked base semiconductor monolayers defining a base semiconductor portion, and at least one non-semiconductor monolayer constrained within a crystal lattice of adjacent base semiconductor portions. Moreover, forming at least one of the base semiconductor portions may include overgrowing the at least one base semiconductor portion and etching back the overgrown at least one base semiconductor portion.

Trenches are formed in a semiconductor layer of a semiconductor substrate. A mixture that contains trichlorosilane and hydrogen gas is fed into a process chamber containing the semiconductor substrate. A barometric pressure in the process chamber is at least 50% of standard atmosphere. The trenches are filled with epitaxially deposited crystalline silicon.

A Group III nitride semiconductor containing: a RAMO.sub.4 substrate containing a single crystal represented by the general formula RAMO.sub.4 (wherein R represents one or a plurality of trivalent elements selected from the group consisting of Sc, In, Y, and a lanthanoid element, A represents one or a plurality of trivalent elements selected from the group consisting of Fe (III), Ga, and Al, and M represents one or a plurality of divalent elements selected from the group consisting of Mg, Mn, Fe(II), Co, Cu, Zn, and Cd), and a Group III nitride crystal disposed above the RAMO.sub.4 substrate, having therebetween a dissimilar film that contains a material different from the RAMO.sub.4 substrate, and has plural openings.

A method of forming a semiconductor structure includes forming an opening in a dielectric layer, forming a recess in an exposed part of a substrate, and forming a lattice-mismatched crystalline semiconductor material in the recess and opening.

Lattice-mismatched epitaxial films formed proximate non-crystalline sidewalls. Embodiments of the invention include formation of facets that direct dislocations in the films to the sidewalls.

One aspect of the disclosure relates to a method of forming a semiconductor structure. The method may include: forming a set of openings within a substrate; forming an insulator layer within each opening in the set of openings; recessing the substrate between adjacent openings containing the insulator layer in the set of openings to form a set of insulator pillars on the substrate; forming sigma cavities within the recessed substrate between adjacent insulator pillars in the set of insulator pillars; and filling the sigma cavities with a semiconductor material over the recessed substrate between adjacent insulator pillars.

A method for manufacturing a semiconductor structure comprises the steps of: providing a substrate including a first semiconductor material; forming a dielectric layer on a surface of the substrate; forming an opening in the dielectric layer having a bottom reaching the substrate; providing a second semiconductor material in the opening and on the substrate, the second semiconductor material being en-capsulated by a further dielectric material thereby forming a filled cavity; melting the second semiconductor material in the cavity; recrystallizing the second semi-conductor material in the cavity; laterally removing the second semiconductor material at least partially for forming a lateral surface at the second semiconductor material; and forming a third semiconductor material on the lateral surface of the second semiconductor material, wherein the third semiconductor material is different from the second semiconductor material.

In one aspect, a method of forming a trench in a semiconductor material includes forming a first dielectric layer on a semiconductor substrate. The first dielectric layer includes first openings. An epitaxial layer is grown on the semiconductor substrate by an epitaxial lateral overgrowth process. The first openings are filled by the epitaxial layer and the epitaxial layer is grown onto adjacent portions of the first dielectric layer so that part of the first dielectric layer is uncovered by the epitaxial layer and a gap forms between opposing sidewalls of the epitaxial layer over the part of the first dielectric layer that is uncovered by the epitaxial layer. The gap defines a first trench in the epitaxial layer that extends to the first dielectric layer.