1455 results about "Single crystal substrate" patented technology

A freestanding GaN single crystal substrate is made by the steps of preparing a (111) GaAs single crystal substrate, forming a mask having periodically arranged windows on the (111) GaAs substrate, making thin GaN buffer layers on the GaAs substrate in the windows of the mask, growing a GaN epitaxial layer on the buffer layers and the mask by an HVPE or an MOC, eliminating the GaAs substrate and the mask away and obtaining a freestanding GaN single crystal substrate. The GaN single crystal has a diameter larger than 20 mm and a thickness more than 0.07 mm, being freestanding and substantially distortion-free.

An electronic device comprises a body including a single crystal region on a major surface of the body. The single crystal region has a hexagonal crystal lattice that is substantially lattice-matched to graphene, and a at least one epitaxial layer of graphene is disposed on the single crystal region. In a currently preferred embodiment, the single crystal region comprises multilayered hexagonal BN. A method of making such an electronic device comprises the steps of: (a) providing a body including a single crystal region on a major surface of the body. The single crystal region has a hexagonal crystal lattice that is substantially lattice-matched to graphene, and (b) epitaxially forming a at least one graphene layer on that region. In a currently preferred embodiment, step (a) further includes the steps of (a1) providing a single crystal substrate of graphite and (a2) epitaxially forming multilayered single crystal hexagonal BN on the substrate. The hexagonal BN layer has a surface region substantially lattice-matched to graphene, and step (b) includes epitaxially forming at least one graphene layer on the surface region of the hexagonal BN layer. Applications to FETs are described.

A process for selectively freeing an epitaxial layer from a single crystal substrate upon which it was grown, by providing a first substrate; depositing a separation layer on the first substrate; depositing on the separation layer a sequence of layers of semiconductor material forming a solar cell; mounting and bonding a thin flexible support having a coefficient of thermal expansion substantially greater than that of the adjacent semiconductor material on top of the sequence of layers at an elevated temperature; and etching the separation layer while the temperature of the support and layers of semiconductor material decrease, so that the support and the attached layer curls away from the first substrate in view of their differences in coefficient of thermal expansion, so as to remove the epitaxial layer from the substrate.

A semiconductor device includes a single crystal substrate and a dielectric layer overlying the substrate. The dielectric layer includes at least one opening having a first portion and an overlying second portion. The first portion has a depth and width, such that an aspect ratio of the depth to width is greater than one. The semiconductor device further includes a first material having a first portion and a second portion, the first portion of the first material filling the first portion of the at least one opening. Defects for relaxing strain at an interface between the first material and the substrate material exist only within the first portion of the first material due to the aspect ratio being greater than one. The second portion of the first material is substantially defect free. Furthermore, the second portion of the first material and an overlying second material different than the first material fill the overlying second portion of the at least one opening. The second material has a thickness which is less than a critical thickness to maintain the second material in a strained state. The strained second material functions as a channel for charge carriers.

The method of making a GaN single crystal substrate comprises a mask layer forming step of forming on a GaAs substrate 2 a mask layer 8 having a plurality of opening windows 10 disposed separate from each other; and an epitaxial layer growing step of growing on the mask layer 8 an epitaxial layer 12 made of GaN.

A self-standing gallium nitride-based semiconductor single crystal substrate has a surface (Ga-face) mirror-polished, and a rear surface (N-face) having an arithmetic mean roughness Ra of 1 micrometer or more and 10 micrometers or less. A nitride semiconductor device is fabricated such that, before the gallium nitride-based semiconductor single crystal substrate is attached to a substrate holder of a vapor phase growth apparatus, the substrate is adjusted such that its rear surface (N-face) has a arithmetic mean roughness Ra to be in face-to-face contact with the substrate holder.

In a method of manufacturing a piezoelectric device, a compressive stress film is formed on a back surface of a piezoelectric single crystal substrate opposite to a surface on an ion-implanted side. The compressive stress film compresses the surface on the ion-implanted side of the piezoelectric single crystal substrate. The compressive stress produced by the compressive stress film is applied to half of the piezoelectric single crystal substrate on the ion-implanted side with respect to the center line of the thickness of the piezoelectric single crystal substrate to prevent the piezoelectric single crystal substrate from warping. A supporting substrate is then bonded to the surface of a bonding film on the flat piezoelectric single crystal substrate. The joined body of the piezoelectric single crystal substrate and the supporting substrate is then heated to initiate isolation at the ion-implanted portion as the isolation plane.

A process for selectively freeing an epitaxial layer from a single crystal substrate upon which it was grown, by providing a first substrate; depositing a separation layer on said first substrate; depositing on said separation layer a sequence of layers of semiconductor material forming a solar cell; mounting and bonding a surrogate substrate on top of the sequence of layers; attaching a connecting link element to at least two opposed points on the periphery of the surrogate substrate; and etching said separation layer while applying tension to said link element so as to remove said epitaxial layer from said first substrate.