Abstract: The disclosure provides a preparation method of GaN field effect transistor based on diamond substrate, and relates to the technical field of semiconductor manufacturing. The method includes the following steps: preparing a GaN heterojunction layer on the front-side of a SiC substrate; thinning the SiC substrate; etching the SiC substrate; growing a diamond layer; removing a sacrificial layer and the diamond layer on the sacrificial layer; preparing a source electrode, a drain electrode and a gate electrode on the front surface of the GaN heterojunction layer; etching the SiC substrate and the GaN heterojunction layer to form a source through hole communicated with the source electrode; and removing the through hole mask layer, and preparing back grounding metal to complete the preparation of the diamond substrate GaN transistor device.

Abstract: Disclosed are artificial intelligence (AI) based systems and methods for characterizing corneal shape abnormalities. The methods and systems of the present disclosure utilize AI models comprising neural networks for disease classification based on maps of corneal shape, thickness, and reflectance. These methods may be used to differentiate corneas having keratoconus from other conditions which may cause distortion of corneal shape, such as warpage of the cornea. The present system is amenable to automation and may be implemented in an integrated system or provided in the form of software encoded on a computer-readable medium.

Abstract: The disclosure provides a normally-off gallium oxide field-effect transistor structure and a preparation method therefor, and relates to the technical field of semiconductor device. The normally-off gallium oxide field-effect transistor structure comprises a substrate layer and an n-type doped gallium oxide channel layer from bottom to top. The n-type doped gallium oxide channel layer is provided with a source, a drain, and a gate. The gate is located between the source and the drain. A no-electron channel region is provided in the n-type doped gallium oxide channel layer located below the gate.

Abstract: The disclosure is applicable for the technical field of semiconductor devices manufacturing, and provides a gallium oxide SBD terminal structure. The gallium oxide SBD terminal structure comprises a cathode metal layer, an N+ high-concentration substrate layer, an N? low-concentration Ga2O3 epitaxial layer and an anode metal layer from bottom to top, wherein the N? low-concentration Ga2O3 epitaxial layer is within a range of certain thickness close to the anode metal layer; and a doping concentration below the anode metal layer is greater than a doping concentration on two sides of the anode metal layer. Namely, only a doping concentration of the part outside the corresponding area of the anode metal layer is changed, so that the breakdown voltage of the gallium oxide SBD terminal structure is improved under the condition of guaranteeing low on resistance.

Abstract: The disclosure provides a preparation method of GaN field effect transistor based on diamond substrate, and relates to the technical field of semiconductor manufacturing. The method includes the following steps: preparing a GaN heterojunction layer on the front-side of a SiC substrate; thinning the SiC substrate; etching the SiC substrate; growing a diamond layer; removing a sacrificial layer and the diamond layer on the sacrificial layer; preparing a source electrode, a drain electrode and a gate electrode on the front surface of the GaN heterojunction layer; etching the SiC substrate and the GaN heterojunction layer to form a source through hole communicated with the source electrode; and removing the through hole mask layer, and preparing back grounding metal to complete the preparation of the diamond substrate GaN transistor device.

Abstract: A ultraviolet detector includes a substrate; a first epitaxial layer that is a heavily doped epitaxial layer and located on the substrate, a second epitaxial layer located on the first epitaxial layer, where the second epitaxial layer is a lightly doped epitaxial layer, or a double-layer or multi-layer structure composed of at least one lightly doped epitaxial layer and at least one heavily doped epitaxial layer; an ohmic contact layer located on the second epitaxial layer or formed in the second epitaxial layer, where the ohmic contact layer is a graphical heavily doped layer; and a first metal electrode layer located on the ohmic contact layer.

Abstract: The disclosure is related to the technical field of semiconductors, and provides a method for manufacturing a tilted mesa and a method for manufacturing a detector. The method for manufacturing a tilted mesa comprises: coating a photoresist layer on a mesa region of a chip; heating the chip on which the photoresist layer is coated from a first preset temperature to a second preset temperature; performing etching processing on the heated chip, so as to manufacture a mesa having a preset tilting angle; and removing the photoresist layer on the mesa region of the chip after the mesa is manufactured.

Abstract: A method for preparing an avalanche photodiode includes preparing a mesa on a wafer, growing a sacrificial layer on an upper surface of the wafer and a side surface of the mesa, removing the sacrificial layer in an ohmic contact electrode region of the wafer, preparing an ohmic contact electrode in the ohmic contact electrode region of the wafer, removing the sacrificial layer in a non-mesa region of the wafer, growing a passivation layer on the upper surface of the wafer and the side surface of the mesa, removing the passivation layer on the upper surface of the mesa of the wafer and the passivation layer in the non-mesa region of the wafer corresponding to the ohmic contact electrode region, and removing the sacrificial layer on the upper surface of the mesa of the wafer.

Abstract: The disclosure provides a silicon carbide detector and a preparation method therefor. The silicon carbide detector comprises: a wafer, the wafer sequentially comprises, from bottom to top, a substrate, a silicon carbide P+ layer, an N-type silicon carbide insertion layer, an N+ type silicon carbide multiplication layer, an N-type silicon carbide absorption layer and a silicon carbide N+ layer; the doping concentration of the N-type silicon carbide insertion layer gradually increases from bottom to top, and the doping concentration of the N-type silicon carbide absorption layer gradually decreases from bottom to top; a mesa is etched on the wafer, and the mesa is etched to an upper surface of the silicon carbide P+ layer; an N-type electrode is arranged on an upper surface of the mesa, and a P-type electrode is arranged on an upper surface of a non-mesa region.

Abstract: The present disclosure discloses a method for preparing an isolation area of a gallium oxide device, the method comprising: depositing a mask layer on a gallium oxide material; removing a preset portion region of the mask layer; preparing an isolation area in a position, corresponding to the preset portion region, on the gallium oxide material by using a high-temperature oxidation technique, with the isolation area being located between active areas of the gallium oxide device; and removing the remaining mask layer on the gallium oxide material. In the disclosure, the isolation area is prepared by using the high-temperature oxidation technique, which prevents damage to the gallium oxide device during the preparation of the isolation area, thereby achieving isolation between the active areas of the gallium oxide device.

Abstract: The disclosure provides a method for preparing a self-aligned surface channel field effect transistor, and provides a power device. The method includes the following steps: depositing a first metal mask layer; preparing a first photoresist layer; forming a source area pattern and a drain area pattern; depositing a source metal layer and a drain metal layer on the source area pattern and the drain area pattern; peeling off and removing the first photoresist layer; depositing a second metal mask layer; preparing a second photoresist layer, and forming at least one gate area pattern closer toward the source metal layer by performing exposure and development; removing the first metal mask layer and the second metal mask layer between the source metal layer and the drain metal layer by a wet corrosion; depositing a gate metal layer on the gate area pattern; and peeling off and removing the second photoresist layer.

Abstract: The present disclosure discloses an enhancement-mode field effect transistor. This enhancement-mode field effect transistor includes a substrate, a channel layer formed on an upper surface of the substrate, a source electrode and a drain electrode respectively formed on both sides of the channel layer, and a gate electrode formed on an upper surface of the channel layer, a region outside the corresponding region of the gate electrode in the channel layer is provided with a carrier-free region. Carriers are absent in the carrier-free region, and carriers are present in the remaining portion of the channel layer. The carrier-free region is not disposed below the gate electrode, but is disposed outside the corresponding region of the gate electrode in the channel layer, and the threshold voltage of the device can be regulated by regulating the width and number of the carrier-free region.

Abstract: The disclosure provides a normally-off gallium oxide field-effect transistor structure and a preparation method therefor, and relates to the technical field of semiconductor device. The normally-off gallium oxide field-effect transistor structure comprises a substrate layer and an n-type doped gallium oxide channel layer from bottom to top. The n-type doped gallium oxide channel layer is provided with a source, a drain, and a gate. The gate is located between the source and the drain. A no-electron channel region is provided in the n-type doped gallium oxide channel layer located below the gate.

Abstract: The disclosure is applicable for the technical field of semiconductor devices manufacturing, and provides a gallium oxide SBD terminal structure. The gallium oxide SBD terminal structure comprises a cathode metal layer, an N+ high-concentration substrate layer, an N? low-concentration Ga2O3 epitaxial layer and an anode metal layer from bottom to top, wherein the N? low-concentration Ga2O3 epitaxial layer is within a range of certain thickness close to the anode metal layer; and a doping concentration below the anode metal layer is greater than a doping concentration on two sides of the anode metal layer. Namely, only a doping concentration of the part outside the corresponding area of the anode metal layer is changed, so that the breakdown voltage of the gallium oxide SBD terminal structure is improved under the condition of guaranteeing low on resistance.

Abstract: A method for preparing an avalanche photodiode includes preparing a mesa on a wafer, growing a sacrificial layer on an upper surface of the wafer and a side surface of the mesa, removing the sacrificial layer in an ohmic contact electrode region of the wafer, preparing an ohmic contact electrode in the ohmic contact electrode region of the wafer, removing the sacrificial layer in a non-mesa region of the wafer, growing a passivation layer on the upper surface of the wafer and the side surface of the mesa, removing the passivation layer on the upper surface of the mesa of the wafer and the passivation layer in the non-mesa region of the wafer corresponding to the ohmic contact electrode region, and removing the sacrificial layer on the upper surface of the mesa of the wafer.

Abstract: The disclosure provides a silicon carbide detector and a preparation method therefor. The silicon carbide detector comprises: a wafer, the wafer sequentially comprises, from bottom to top, a substrate, a silicon carbide P+ layer, an N-type silicon carbide insertion layer, an N+ type silicon carbide multiplication layer, an N-type silicon carbide absorption layer and a silicon carbide N+ layer; the doping concentration of the N-type silicon carbide insertion layer gradually increases from bottom to top, and the doping concentration of the N-type silicon carbide absorption layer gradually decreases from bottom to top; a mesa is etched on the wafer, and the mesa is etched to an upper surface of the silicon carbide P+ layer; an N-type electrode is arranged on an upper surface of the mesa, and a P-type electrode is arranged on an upper surface of a non-mesa region.

Abstract: The disclosure is related to the technical field of semiconductors, and provides a method for manufacturing a tilted mesa and a method for manufacturing a detector. The method for manufacturing a tilted mesa comprises: coating a photoresist layer on a mesa region of a chip; heating the chip on which the photoresist layer is coated from a first preset temperature to a second preset temperature; performing etching processing on the heated chip, so as to manufacture a mesa having a preset tilting angle; and removing the photoresist layer on the mesa region of the chip after the mesa is manufactured.

Abstract: The present disclosure discloses a method for preparing an isolation area of a gallium oxide device, the method comprising: depositing a mask layer on a gallium oxide material; removing a preset portion region of the mask layer; preparing an isolation area in a position, corresponding to the preset portion region, on the gallium oxide material by using a high-temperature oxidation technique, with the isolation area being located between active areas of the gallium oxide device; and removing the remaining mask layer on the gallium oxide material. In the disclosure, the isolation area is prepared by using the high-temperature oxidation technique, which prevents damage to the gallium oxide device during the preparation of the isolation area, thereby achieving isolation between the active areas of the gallium oxide device.

Abstract: An enhanced HFET, comprising a HFET device body.

Abstract: The disclosure provides a method for preparing a self-aligned surface channel field effect transistor, and provides a power device. The method includes the following steps: depositing a first metal mask layer; preparing a first photoresist layer; forming a source area pattern and a drain area pattern; depositing a source metal layer and a drain metal layer on the source area pattern and the drain area pattern; peeling off and removing the first photoresist layer; depositing a second metal mask layer; preparing a second photoresist layer, and forming at least one gate area pattern closer toward the source metal layer by performing exposure and development; removing the first metal mask layer and the second metal mask layer between the source metal layer and the drain metal layer by a wet corrosion; depositing a gate metal layer on the gate area pattern; and peeling off and removing the second photoresist layer.