Laser lift off systems and methods may be used to provide monolithic laser lift off with minimal cracking by reducing the size of one or more beam spots in one or more dimensions to reduce plume pressure while maintaining sufficient energy to provide separation. By irradiating irradiation zones with various shapes and in various patterns, the laser lift off systems and methods use laser energy more efficiently, reduce cracking when separating layers, and improve productivity. Some laser lift off systems and methods described herein separate layers of material by irradiating non-contiguous irradiation zones with laser lift off zones (LOZs) that extend beyond the irradiation zones. Other laser lift off systems and methods described herein separate layers of material by shaping the irradiation zones and by controlling the overlap of the irradiation zones in a way that avoids uneven exposure of the workpiece. Consistent with at least one embodiment, a laser lift off system and method may be used to provide monolithic lift off of one or more epitaxial layers on a substrate of a semiconductor wafer.

A carrier substrate includes a base layer, an antireflection layer, and an energy absorption layer, wherein the antireflection layer is formed on one surface of the base layer and allows an elastic wave generated by a first laser beam transmitted through an element adhesively bonded to the antireflection layer to be transmitted through the base layer without being reflected towards the element, the first laser beam being applied to the element through a source substrate of the element, and the energy absorption layer is formed between the base layer and the antireflection layer to be aligned with the element, and evaporates upon energy absorption.

A method for the reuse of gallium nitride (GaN) epitaxial substrates uses band-gap-selective photoelectrochemical (PEC) etching to remove one or more epitaxial layers from bulk or free-standing GaN substrates without damaging the substrate, allowing the substrate to be reused for further growth of additional epitaxial layers. The method facilitates a significant cost reduction in device production by permitting the reuse of expensive bulk or free-standing GaN substrates.

Techniques for fabricating thin epitaxial SiC device wafers are described. A bulk SiC wafer is used to provide a seed layer of a thin layer of SiC for epitaxially growing SiC. The seed layer is exfoliated from the bulk SiC after bonding the bulk SiC to a handle substrate. The bulk SiC wafer from which the thin layer of SiC is exfoliated may be re-used in fabricating subsequent thin film epitaxial SiC wafers. After growing epitaxial SiC from the seed layer on the handle substrate, devices may be fabricated in the epitaxial SiC and the handle substrate can be removed. The handle substrate can be re-used in fabricating subsequent thin film epitaxial SiC wafers. The epitaxial SiC can be cut into dies and packaged as an SiC chip or bonded to another substrate, such as a silicon substrate with devices formed thereon.

A stack including a silicon oxide layer, a germanium-containing layer, and a III-V compound semiconductor layer is formed over a substrate. An alternating stack of insulating layers and spacer material layers is formed over the III-V compound semiconductor layer. The spacer material layers are formed as, or are subsequently replaced with, electrically conductive layers. Memory openings are formed through the alternating stack and into the III-V compound semiconductor layer. Memory opening fill structures including a memory film and a vertical semiconductor channel are formed in the memory openings. The vertical semiconductor channels can include a III-V compound semiconductor channel material that is electrically connected to the III-V compound semiconductor layer. The substrate and at least a portion of the silicon oxide layer can be subsequently detached.

A lift-off method includes a relocation substrate joining step of joining a relocation substrate to a surface of an optical device layer of an optical device wafer with a joining member interposed therebetween, thereby forming a composite substrate, a buffer layer breaking step of applying a pulsed laser beam having a wavelength transmittable through an epitaxy substrate and absorbable by a buffer layer to the buffer layer from a reverse side of the epitaxy substrate of the optical device wafer of the composite substrate, thereby breaking the buffer layer, and an optical device layer relocating step of peeling off the epitaxy substrate from the optical device layer, thereby relocating the optical device layer to the relocation substrate. In the buffer layer breaking step, irradiating conditions of the pulsed la-ser beam are changed for respective ring-shaped areas of the buffer layer, and the pulsed laser beam is applied to the optical device wafer under the changed irradiating conditions.

The present disclosure describes a method that includes forming a first two-dimensional (2D) layer on a first substrate and attaching a second 2D layer to a carrier film. The method also includes bonding the second 2D layer to the first 2D layer to form a heterostack including the first and second 2D layers. The method further includes separating the first 2D layer of the heterostack from the first substrate and attaching the heterostack to a second substrate. The method further includes removing the carrier film from the second 2D layer.

Methods for obtaining a free-standing thick (>5 μm) epitaxial material layer or heterostructure stack and for transferring the thick epitaxial layer or stack to an arbitrary substrate. A thick epitaxial layer or heterostructure stack is formed on an engineered substrate, with a sacrificial layer disposed between the epitaxial layer and the engineered substrate. When the sacrificial layer is removed, the epitaxial layer becomes a thick freestanding layer that can be transferred to an arbitrary substrate, with the remaining engineered substrate being reusable for subsequent material layer growth. In an exemplary case, the material layer is a GaN layer and can be selectively bonded to an arbitrary substrate to selectively produce a Ga-polar or an N-polar GaN layer.

A wafer composite includes a handle substrate, an auxiliary layer formed on a first main surface of the handle substrate, and a silicon carbide structure formed over the auxiliary layer. The handle substrate is subjected to laser radiation that modifies crystalline material along a focal plane in the handle substrate. The focal plane is parallel to the first main surface. The auxiliary layer is configured to stop propagation of microcracks that the laser radiation may generate in the handle substrate.

A method for making a selective-area lift-off thin film comprises depositing a van der Waals (vdW) buffer on a substrate; depositing a thin film material (or device structure) on the van der Waals buffer; depositing an adhesion layer on the thin film material; forming a stressor layer on top of the thin film layer; and bonding a handle layer to the stressor layer. Force may be applied to the layered structure by one or more of rolling, bending, and shearing. The area selected for lift-off may be defined by one of laser cutting and mechanical scribing. The vdW buffer includes one or more of hBN, graphite, and graphene. The handle layer is a one of a polyimide tape, thermal release tape, UV release tape, water- or solvent-soluble tape, Kapton tape, and Scotch tape. The stressor layer is a metal film, e.g. Ni, Cr, Ti.