公开(公告)号：US20220352409A1

公开(公告)日：2022-11-03

申请号：US17862744

申请日：2022-07-12

Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA

Inventor： Takeshi Kamikawa ,  Srinivas Gandrothula ,  Hongjian Li ,  Daniel A. Cohen

IPC: H01L33/00 ,  H01L25/075 ,  H01S5/02 ,  H01S5/343

Abstract: A method of removing a substrate, comprising: forming a growth restrict mask with a plurality of striped opening areas directly or indirectly upon a GaN-based substrate; and growing a plurality of semiconductor layers upon the GaN-based substrate using the growth restrict mask, such that the growth extends in a direction parallel to the striped opening areas of the growth restrict mask, and growth is stopped before the semiconductor layers coalesce, thereby resulting in island-like semiconductor layers. A device is processed for each of the island-like semiconductor layers. Etching is performed until at least a part of the growth restrict mask is exposed. The devices are then bonded to a support substrate. The GaN-based substrate is removed from the devices by a wet etching technique that at least partially dissolves the growth restrict mask. The GaN substrate that is removed then can be recycled.

公开(公告)号：US20220123166A1

公开(公告)日：2022-04-21

申请号：US17422807

申请日：2020-01-16

Applicant: The Regents of the University of California

Inventor： Takeshi Kamikawa ,  Srinivas Gandrothula ,  Masahiro Araki

IPC: H01L33/00 ,  H01L33/28

Abstract: An epitaxial lateral overgrowth (ELO) layer is grown on an opening area of a substrate, wherein the ELO layer is higher than a surface 5 of a trench in the substrate. The trench is apt to form a symmetric shape of the ELO layer, which renders it suitable for flip-chip bonding The shape of the ELO layer has a depressed surface region at a back side of a bar formed by the ELO layer. A cleaving point is located higher than the bottom of the ELO layer, so that a force can be efficiently applied to 10 the cleaving point for removing the bar.

公开(公告)号：US20230411554A1

公开(公告)日：2023-12-21

申请号：US18248623

申请日：2021-10-22

Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA

Inventor： Srinivas Gandrothula ,  Takeshi Kamikawa

IPC: H01L33/00 ,  H01L25/075

CPC classification number: H01L33/0075 ,  H01L33/0093 ,  H01L25/0753

Abstract: A method for fabricating and transferring high quality and manufacturable light-emitting devices, such as small sized light-emitting diodes (mLEDs), using epitaxial lateral overgrowth (ELO) and isolation methods. III-nitride ELO layers are grown on a host substrate using a growth restrict mask, and III-nitride device layers are grown on wings of the III-nitride ELO layers. The resulting devices are isolated from the host substrate while attached by a connecting link comprising an epitaxial or non-epitaxial bridge. A regrowth is performed on selected mesas of the device layers to realize improved devices with the help of the bridge. The bridge is broken, and the devices are then plucked from the host substrate and placed on a display panel.

公开(公告)号：US11508620B2

公开(公告)日：2022-11-22

申请号：US16642298

申请日：2018-09-17

Applicant: The Regents of the University of California

Inventor： Takeshi Kamikawa ,  Srinivas Gandrothula ,  Hongjian Li

IPC: H01L21/78 ,  H01L33/00 ,  H01L21/02 ,  H01S5/02

Abstract: A method of removing a substrate from III-nitride based semiconductor layers with a cleaving technique. A growth restrict mask is formed on or above a substrate, and one or more III-nitride based semiconductor layers are grown on or above the substrate using the growth restrict mask. The III-nitride based semiconductor layers are bonded to a support substrate or film, and the III-nitride based semiconductor layers are removed from the substrate using a cleaving technique on a surface of the substrate. Stress may be applied to the III-nitride based semiconductor layers, due to differences in thermal expansion between the III-nitride substrate and the support substrate or film bonded to the III-nitride based semiconductor layers, before the III-nitride based semiconductor layers are removed from the substrate. Once removed, the substrate can be recycled, resulting in cost savings for device fabrication.

公开(公告)号：US20220165570A1

公开(公告)日：2022-05-26

申请号：US17434863

申请日：2020-03-13

Applicant: The Regents of the University of California

Inventor： Takeshi Kamikawa ,  Masahiro Araki ,  Srinivas Gandrothula

IPC: H01L21/02 ,  H01L21/78

Abstract: Epitaxial lateral overgrowth (ELO) III-nitride layers are grown on or above an opening area of a growth restrict mask deposited on a substrate, wherein the growth of the ELO III-nitride layers and/or a subsequent regrowth layer form one or more voids. III-nitride device layers are grown on or above the ELO III-nitride layers and/or regrowth layer. Stress is applied to a breaking point at the substrate, with the voids assisting the application of stress, so that a bar of devices comprised of the III-nitride device layers, the ELO III-nitride layers and the regrowth layer is removed from the substrate. The voids release stress from the growth restrict mask, which helps prevent cracks. Decomposition of the growth restrict mask is avoided to prevent compensation of p-type layers.

公开(公告)号：US20220108883A1

公开(公告)日：2022-04-07

申请号：US17429570

申请日：2020-03-02

Applicant: The Regents of the University of California

Inventor： Takeshi Kamikawa ,  Srinivas Gandrothula

IPC: H01L21/02 ,  H01L29/20

Abstract: A method for flattening a surface on an epitaxial lateral overgrowth (ELO) layer, resulting in obtaining a smooth surface with island-like III-nitride semiconductor layers. The island-like III-nitride semiconductor layers are formed by stopping the growth of the ELO layers before they coalesce to each other. Then, a growth restrict mask is removed before at least some III-nitride device layers are grown. Removing the mask decreases an excess gases supply to side facets of the island-like III-nitride semiconductor layers, which can help to obtain a smooth surface on the island-like III-nitride semiconductor layers. The method also avoids compensation of a p-type layer by decomposed n-type dopant from the mask, such as Silicon and Oxygen atoms.

公开(公告)号：US20240413610A1

公开(公告)日：2024-12-12

申请号：US18699439

申请日：2022-10-24

Applicant: The Regents of the University of California

Inventor： Srinivas Gandrothula ,  Shuji Nakamura ,  Steven P. DenBaars

IPC: H01S5/183 ,  H01S5/02 ,  H01S5/30

Abstract: Methods for fabricating a vertical cavity surface emitting laser (VCSEL) using epitaxial lateral overgrowth (ELO). The ELO layers comprise island-like III-nitride semiconductor layers grown on a substrate using a growth restrict mask, wherein the island-like III-nitride semiconductor layers comprise a light emitting resonant cavity. An aperture for the resonant cavity is fabricated on a wing of the ELO layers with distributed Bragg reflector (DBR) mirrors formed on bottom and top regions of the wing of the ELO layers.

公开(公告)号：US20240405158A1

公开(公告)日：2024-12-05

申请号：US18701367

申请日：2022-10-28

Applicant: The Regents of the University of California

Inventor： Srinivas Gandrothula ,  Shuji Nakamura ,  Steven P. DenBaars

IPC: H01L33/10 ,  H01L33/00 ,  H01L33/22

Abstract: A method for fabricating epitaxial light control features, without reactive ion etching or wet etching, when active layers are included. The epitaxial light control features comprise light extraction or guiding structures integrated on an epitaxial layer of a light emitting device such as a light emitting diode. The light extraction or guiding structures are fabricated on the epitaxial layer using an epitaxial lateral overgrowth (ELO) technique. The epitaxial light control features can have many different shapes and can be fabricated with standard processing techniques, making them highly manufacturable at costs similar to standard processing techniques.

公开(公告)号：US12087577B2

公开(公告)日：2024-09-10

申请号：US17048383

申请日：2019-05-17

Applicant: The Regents of the University of California

Inventor： Takeshi Kamikawa ,  Srinivas Gandrothula

IPC: H01L21/02

CPC classification number: H01L21/02389 ,  H01L21/0242 ,  H01L21/02436 ,  H01L21/02573

Abstract: A method for dividing a bar of one or more devices. The bar is comprised of island-like III-nitride-based semiconductor layers grown on a substrate using a growth restrict mask; the island-like III-nitride-based semiconductor layers are removed from the substrate using an Epitaxial Lateral Overgrowth (ELO) method; and then the bar is divided into the one or more devices using a cleaving method.

公开(公告)号：US12051765B2

公开(公告)日：2024-07-30

申请号：US17422807

申请日：2020-01-16

Applicant: The Regents of the University of California

Inventor： Takeshi Kamikawa ,  Srinivas Gandrothula ,  Masahiro Araki

IPC: H01L33/00 ,  H01L33/28

CPC classification number: H01L33/0093 ,  H01L33/0075 ,  H01L33/28

Abstract: An epitaxial lateral overgrowth (ELO) layer is grown on an opening area of a substrate, wherein the ELO layer is higher than a surface 5 of a trench in the substrate. The trench is apt to form a symmetric shape of the ELO layer, which renders it suitable for flip-chip bonding The shape of the ELO layer has a depressed surface region at a back side of a bar formed by the ELO layer. A cleaving point is located higher than the bottom of the ELO layer, so that a force can be efficiently applied to 10 the cleaving point for removing the bar.