Abstract:
A method for manufacturing a light emitting diode includes following steps: providing a substrate; forming a buffer layer on the substrate; forming a transitional layer on the buffer layer, the buffer layer being made of InGaN; forming an epitaxial layer on the transitional layer; activating the transitional layer by a way of radiating the transitional layer using laser; and when radiated with a laser, the transitional layer separates from the epitaxial layer.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to Chinese Patent Application No. 201310440192.3 filed on Sep. 25, 2013 in the State Intellectual Property Office Of The P. R. C, the contents of which are incorporated by reference herein. 
       FIELD 
       [0002]    The disclosure relates to a method for manufacturing an LED (light emitting diode). 
       BACKGROUND 
       [0003]    A typical method for manufacturing light emitting diodes (LEDs) includes removing a substrate and a buffer layer formed on the substrate from an epitaxial layer, and it is almost always performed by etching. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]    Implementations of the present technology will now be described, by way of example only, with reference to the attached figures. 
           [0005]      FIG. 1  is a cross-sectional view showing an LED in accordance with an exemplary embodiment of the present disclosure. 
           [0006]      FIG. 2  is a cross-sectional view showing removing a substrate, a buffer layer and a transitional layer from the LED of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0007]    It will be appreciated that for simplicity and clarity of illustration, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein can be practiced without these specific details. In other instances, methods, procedures and components have not been described in detail so as not to obscure the related relevant feature being described. Also, the description is not to be considered as limiting the scope of the embodiments described herein. The drawings are not necessarily to scale and the proportions of certain parts have been exaggerated to better illustrate details and features of the present disclosure. The description is not to be considered as limiting the scope of the embodiments described herein. 
         [0008]    Several definitions that apply throughout this disclosure will now be presented. The term “comprising” means “including, but not necessarily limited to”; it specifically indicates open-ended inclusion or membership in a so-described combination, group, series and the like. The term “coupled” is defined as connected, whether directly or indirectly through intervening components, and is not necessarily limited to physical connections. The connection can be such that the objects are permanently connected or releasably connected. The term “electronically coupled” can include any coupling that is via a wired or wireless connection. The electronic coupling can be through one or more components or it can include a direct connection between the described components. 
         [0009]    Referring to  FIG. 1 , providing a substrate  10 . In at least one embodiment, the substrate  10  is made of sapphire. 
         [0010]    Forming a buffer layer  20  on the substrate  10 . The buffer layer  20  is formed by a way of Metal-Organic Chemical Vapor Deposition (MOCVD), Molecular Beam Epitaxy (MBE), or Hydride Vapor Phase Epitaxy (HVPE). In at least one embodiment, the buffer layer  20  is an un-doped GaN layer. 
         [0011]    Forming a transitional layer  30  on the buffer layer  20 . The transitional layer  30  is formed by a way of Metal-Organic Chemical Vapor Deposition (MOCVD), Molecular Beam Epitaxy (MBE), or Hydride Vapor Phase Epitaxy (HVPE). In at least one embodiment, the transitional layer  30  is an InGaN film, and a thickness of the transitional layer  30  varies from 100 A to 200 A. 
         [0012]    Forming an epitaxial layer  40  on the transitional layer  30 . The transitional layer  30  is formed by a way of Metal-Organic Chemical Vapor Deposition (MOCVD), Molecular Beam Epitaxy (MBE), or Hydride Vapor Phase Epitaxy (HVPE). The epitaxial layer  40  includes a first semiconductor layer  41 , an active layer  42  and a second semiconductor layer  43 . The first semiconductor layer  41  is formed on the transitional layer  30 , the active layer  42  is formed on the first semiconductor  41  and the second semiconductor layer  43  is formed on the active layer  42 . In at least one embodiment, the first semiconductor  41  is an N-type GaN layer, the active layer  42  is a multi-quantum well GaN layer, and the second semiconductor  43  is a P-type GaN layer. 
         [0013]    Referring to  FIG. 2 , activating the transitional layer  30  by a way of radiating the transitional layer  30  using a laser. In at least one embodiment, the transitional layer  30  is subjected to temperatures of 1000-1400° C., and is radiated by laser with wavelengths from 420 nm to 520 nm. And because the wavelength of the laser is larger than 420 nm, the transitional layer  30  can be activated by the laser without affecting the buffer layer  20 . And meanwhile, the transitional layer  30  made of InGaN is heated to contract to represent ball-shaped configurations, which makes the transitional layer  30  separate from the epitaxial layer  40  to obtain an individual LED without the substrate  10 , the buffer layer  20  and the transitional layer  30 . 
         [0014]    According to the above description of the embodiment of the disclosure, by a way of forming the InGaN transitional layer  30  between the buffer layer  20  and the epitaxial layer  40 , and radiating the InGaN transitional layer  30  using layer with wavelengths from 420 nm to 520 nm in temperatures 1000-1400° C., the transitional layer  30  is contracted to separate from the epitaxial layer  40 . 
         [0015]    It is to be further understood that even though numerous characteristics and advantages have been set forth in the foregoing description of embodiments, together with details of the structures and functions of the embodiments, the disclosure is illustrative only; and that changes may be made in detail, including in matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. 
         [0016]    The embodiments shown and described above are only examples. Many details are often found in the art such as the other features of a method for manufacturing an LED. Therefore, many such details are neither shown nor described. Even though numerous characteristics and advantages of the present technology have been set forth in the foregoing description, together with details of the structure and function of the present disclosure, the disclosure is illustrative only, and changes may be made in the detail, including in matters of shape, size and arrangement of the parts within the principles of the present disclosure up to, and including the full extent established by the broad general meaning of the terms used in the claims. It will therefore be appreciated that the embodiments described above may be modified within the scope of the claims.