In some embodiments, a selective cyclic (optionally dry) etching of a first surface of a substrate relative to a second surface of the substrate in a reaction chamber by chemical atomic layer etching comprises forming a modification layer using a first plasma and etching the modification layer. The first surface comprises carbon and/or nitride and the second surface does not comprise carbon and/or nitride.

In some embodiments, a selective cyclic (optionally dry) etching of a first surface of a substrate relative to a second surface of the substrate in a reaction chamber by chemical atomic layer etching comprises forming a modification layer using a first plasma and etching the modification layer. The first surface comprises carbon and/or nitride and the second surface does not comprise carbon and/or nitride.

A method of manufacturing a substrate includes forming a support structure by providing a polycrystalline ceramic core, encapsulating the polycrystalline ceramic core in a first adhesion shell, encapsulating the first adhesion shell in a conductive shell, encapsulating the conductive shell in a second adhesion shell, and encapsulating the second adhesion shell in a barrier shell. The method also includes joining a bonding layer to the support structure, joining a substantially single crystalline silicon layer to the bonding layer, forming an epitaxial silicon layer by epitaxial growth on the substantially single crystalline silicon layer, and forming one or more epitaxial III-V layers by epitaxial growth on the epitaxial silicon layer.

A method of manufacturing a substrate includes forming a support structure by providing a polycrystalline ceramic core, encapsulating the polycrystalline ceramic core in a first adhesion shell, encapsulating the first adhesion shell in a conductive shell, encapsulating the conductive shell in a second adhesion shell, and encapsulating the second adhesion shell in a barrier shell. The method also includes joining a bonding layer to the support structure, joining a substantially single crystalline silicon layer to the bonding layer, forming an epitaxial silicon layer by epitaxial growth on the substantially single crystalline silicon layer, and forming one or more epitaxial III-V layers by epitaxial growth on the epitaxial silicon layer.

The disclosure is directed to a method to recover the gate oxide integrity yield of a silicon wafer after rapid thermal anneal in an ambient atmosphere comprising a nitrogen containing gas, such as NH.sub.3 or N.sub.2. Generally, rapid thermal anneals in an ambient atmosphere comprising a nitrogen containing gas, such as NH.sub.3 or N.sub.2 to thereby imprint an oxygen precipitate profile can degrade the GOI yield of a silicon wafer by exposing as-grown crystal defects (oxygen precipitate) and vacancies generated by the silicon nitride film. The present invention restores GOI yield by stripping the silicon nitride layer, which is followed by wafer oxidation, which is followed by stripping the silicon oxide layer.

The disclosure is directed to a method to recover the gate oxide integrity yield of a silicon wafer after rapid thermal anneal in an ambient atmosphere comprising a nitrogen containing gas, such as NH.sub.3 or N.sub.2. Generally, rapid thermal anneals in an ambient atmosphere comprising a nitrogen containing gas, such as NH.sub.3 or N.sub.2 to thereby imprint an oxygen precipitate profile can degrade the GOI yield of a silicon wafer by exposing as-grown crystal defects (oxygen precipitate) and vacancies generated by the silicon nitride film. The present invention restores GOI yield by stripping the silicon nitride layer, which is followed by wafer oxidation, which is followed by stripping the silicon oxide layer.

A method for preparing a GaN substrate material includes: performing in-situ epitaxy on a Ga.sub.2O.sub.3 thin film and a GaN thin film in a multifunctional HVPE growth system. First, the Ga.sub.2O.sub.3 thin film is grown on a substrate such as sapphire by an HVPE-like method, and the Ga.sub.2O.sub.3 is nitrided in an ammonia gas atmosphere to form a GaN/Ga.sub.2O.sub.3 composite thin film. Then, a GaN thick film is grown on the GaN/Ga.sub.2O.sub.3 composite thin film by HVPE to obtain a high-quality GaN thick film material. The Ga.sub.2O.sub.3 layer is removed by chemical etching to obtain a self-supporting GaN substrate material. Or, the conventional laser lift-off method is used to separate the GaN thick film from the heterogeneous substrate such as the sapphire to obtain a GaN self-supporting substrate material.

A method for preparing a GaN substrate material includes: performing in-situ epitaxy on a Ga.sub.2O.sub.3 thin film and a GaN thin film in a multifunctional HVPE growth system. First, the Ga.sub.2O.sub.3 thin film is grown on a substrate such as sapphire by an HVPE-like method, and the Ga.sub.2O.sub.3 is nitrided in an ammonia gas atmosphere to form a GaN/Ga.sub.2O.sub.3 composite thin film. Then, a GaN thick film is grown on the GaN/Ga.sub.2O.sub.3 composite thin film by HVPE to obtain a high-quality GaN thick film material. The Ga.sub.2O.sub.3 layer is removed by chemical etching to obtain a self-supporting GaN substrate material. Or, the conventional laser lift-off method is used to separate the GaN thick film from the heterogeneous substrate such as the sapphire to obtain a GaN self-supporting substrate material.

The disclosed method is for processing a single crystal. The single crystal has a first end, a second end and a longitudinal axis between said first end and said second end. The single crystal comprises a seed crystal, wherein the seed crystal extends at least partially along the longitudinal axis. The method comprises a peripheral surface grinding step of grinding a peripheral surface of the single crystal at least partially along the longitudinal axis. The peripheral surface of the single crystal is ground up to a first distance to the longitudinal axis at least partially along a portion of the longitudinal axis excluding the seed crystal, wherein the first distance is preferably less than an extension of the seed crystal to the longitudinal axis.

The disclosed method is for processing a single crystal. The single crystal has a first end, a second end and a longitudinal axis between said first end and said second end. The single crystal comprises a seed crystal, wherein the seed crystal extends at least partially along the longitudinal axis. The method comprises a peripheral surface grinding step of grinding a peripheral surface of the single crystal at least partially along the longitudinal axis. The peripheral surface of the single crystal is ground up to a first distance to the longitudinal axis at least partially along a portion of the longitudinal axis excluding the seed crystal, wherein the first distance is preferably less than an extension of the seed crystal to the longitudinal axis.