A method for reducing crystalline defects in a semiconductor structure is presented. The method includes epitaxially growing a first crystalline material over a crystalline substrate, epitaxially growing a second crystalline material over the first crystalline material, and patterning and removing portions of the second crystalline material to form openings. The method further includes converting the first crystalline material into a non-crystalline material, depositing a thermally stable material in the openings, depositing a capping layer over the second crystalline material and the thermally stable material to form a substantially enclosed semiconductor structure, and annealing the substantially enclosed semiconductor structure.

A semiconductor device includes a substrate, a first semiconductor layer formed over the substrate, the first semiconductor layer being composed of a nitride semiconductor, a second semiconductor layer formed over the first semiconductor layer, the second semiconductor layer being composed of a nitride semiconductor and a gate electrode, a source electrode, and a drain electrode that are formed over the second semiconductor layer, wherein the source electrode including a plurality of protrusions that penetrate into the second semiconductor layer, and the protrusions having a side surface inclined with respect to a surface of the first semiconductor layer.

A method for reducing crystalline defects in a semiconductor structure is presented. The method includes epitaxially growing a first crystalline material over a crystalline substrate, epitaxially growing a second crystalline material over the first crystalline material, and patterning and removing portions of the second crystalline material to form openings. The method further includes converting the first crystalline material into a non-crystalline material, depositing a thermally stable material in the openings, depositing a capping layer over the second crystalline material and the thermally stable material to form a substantially enclosed semiconductor structure, and annealing the substantially enclosed semiconductor structure.

A method of forming a nanosheet semiconductor device that includes epitaxially forming a stack of at least two repeating nanosheets, the at least two repeating nanosheets including a first nanosheet layer of a first III-V semiconductor material and a second nanosheet layer of a second III-V semiconductor material. A sacrificial gate structure is formed on the stack of the at least two repeating nanosheets. Source and drain regions are epitaxially formed on the second nanosheet layer. The sacrificial gate structure is removed to provide a gate opening. An etch process removes the first nanosheet layer selectively to the second nanosheet layer, wherein the etch process is selective to facets of the material for the first nanosheet layer to provide an inverted apex at the base of the stack. A dielectric layer is deposited filling the inverted apex. A functional gate structure is formed in the gate opening.

A semiconductor device includes a substrate having a channel region; a gate stack over the channel region; a seal spacer covering a sidewall of the gate stack, the seal spacer including silicon nitride; a gate spacer covering a sidewall of the seal spacer, the gate spacer including silicon oxide, the gate spacer having a first vertical portion and a first horizontal portion; and a first dielectric layer covering a sidewall of the gate spacer, the first dielectric layer including silicon nitride.

A method of forming a nanosheet semiconductor device that includes epitaxially forming a stack of at least two repeating nanosheets, the at least two repeating nanosheets including a first nanosheet layer of a first III-V semiconductor material and a second nanosheet layer of a second III-V semiconductor material. A sacrificial gate structure is formed on the stack of the at least two repeating nanosheets. Source and drain regions are epitaxially formed on the second nanosheet layer. The sacrificial gate structure is removed to provide a gate opening. An etch process removes the first nanosheet layer selectively to the second nanosheet layer, wherein the etch process is selective to facets of the material for the first nanosheet layer to provide an inverted apex at the base of the stack. A dielectric layer is deposited filling the inverted apex. A functional gate structure is formed in the gate opening.

A method for manufacturing a semiconductor structure includes preparing a dielectric structure formed with trenches respectively defined by lateral surfaces of the dielectric structure, forming spacer layers on the lateral surfaces, filling an electrically conductive material into the trenches to form electrically conductive features, selectively depositing a blocking layer on the dielectric structure, selectively depositing a dielectric material on the electrically conductive features to form a capping layer, removing the blocking layer and the dielectric structure to form recesses, forming sacrificial features in the recesses, forming a sustaining layer to cover the sacrificial features; and removing the sacrificial features to obtain the semiconductor structure formed with air gaps confined by the sustaining layer and the spacer layers.

Methods and structures for forming epitaxial layers of Ill-nitride materials on patterned foreign substrates with low stacking fault densities are described. Semipolar and nonpolar orientations of GaN that are essentially free from stacking faults may be grown from crystal-growth facets of a patterned substrate. Etching can be used to remove stacking faults if present. Crystal growth with an impurity can eliminate crystal growth from a facet that is responsible for stacking fault formation and permit substantially stacking-fault-free growth of the Ill-nitride material.

The present description concerns a method of manufacturing an insulating trench in a substrate, for an electronic device, comprising the following successive steps: (a) filling a trench formed in the substrate with a first insulating material; (b) depositing a first etch stop layer on the first material; (c) depositing a second layer of a second insulating material on the first etch stop layer; (d) etching down to the etch stop layer; and (e) depositing a third layer made of a third tight material.

A bipolar transistor including a first collector layer, a second collector layer, a base layer, and an emitter layer is disposed on a substrate. Etching characteristics of the second collector layer are different from etching characteristics of the first collector layer and the base layer. In plan view, an edge of an interface between the first collector layer and the second collector layer is disposed inside an edge of a lower surface of the base layer, and an edge of an upper surface of the second collector layer coincides with the edge of the lower surface of the base layer or is disposed inside the edge of the lower surface of the base layer.