Patent Publication Number: US-2009221144-A1

Title: Manufacturing method for nano scale Ge metal structure

Description:
FIELD OF THE INVENTION  
     The present invention is related to a manufacturing method for nano scale Ge, it specifically relates a manufacturing method for Ge metal structure that can form nano-dot structure, nano-disk structure and nano-ring structure at the same time. 
     BACKGROUND OF THE INVENTION  
     The prior art to form nano scale structure Ge is to use the characteristic difference between dielectric layer, for example, Silicon Dioxide (SiO2), Silicon Nitride (Si3N4), Hafnium Dioxide (HfO2), Aluminum Oxide (Al2O3), etc., and semiconductor such as Silicon (Si) or Germanium (Ge), and chemical vapor deposition process (CVD) is used to deposit directly on dielectric layer the Ge or Si nano-dot; for example, an US Patent No. 20040147098. However, in such method, due to the difficulty in the control of the process temperature, the formed nano-dot will have very different quality and homogeneity; moreover, in each chemical vapor deposition process, only one nano structure can be formed. 
     As the technology for forming nano structure of US Patent No. 20020148727 and European Patent No. EP1743392, Alkali Metal and Si or Ge is used to form alloy and to precipitate further into nano structure scale Si or Ge. However, the technical field that this technology can be applied to is smaller, that is, it can only be applied to battery or electrode material and it is very difficult to be applied in industries such as: semiconductor industry, optoelectronic industry and/or biosensor industry, etc. 
     SUMMARY OF THE INVENTION  
     One objective of the present invention is to provide a manufacturing method for nano scale Ge metal structure, which can form simultaneously stable quality and homogeneous nano-dot structure. 
     Another purpose of the present invention is to provide a manufacturing method for nano scale Ge metal structure and in the same time a manufacturing method for forming nano-dot structure, nano-disk structure and nano-ring structure Ge metal structure 
     Yet another purpose of the present invention is to provide a manufacturing method for nano scale Ge metal structure which can be widely used in for example, semiconductor industry, optoelectronic industry and/or biosensor fields, etc. 
     Yet another objective of the present invent-ion is to provide a manufacturing method for nano scale Ge metal structure and the method includes: providing a substrate; forming a dielectric layer on the substrate, coating the substrate surface; etching the dielectric layer for forming openings of different dimensions, for example, a first opening, a second opening and a third opening; and performing a chemical vapor deposition process to deposit Ge metal layer on the first opening, the second opening and the third opening so as to form a first Ge metal structure a second Ge metal structure and a third Ge metal structure. 
     Further another objective of the present invention is to provide a manufacturing method for nano scale Ge metal structure, which includes: providing a Si substrate; using wet cleaning process and 1% HF solution to perform a pre-treatment process on Si substrate; using high temperature furnace to form a 10˜500 nm dielectric layer, for example, Si02, Si3N4, Hf02 on Si substrate; using electron beam direct writing system and active ion micro-lithography process to etch the dielectric layer to form 150˜350 nm first opening, 400˜600 nm second opening and 650˜850 nm third opening; and at 350˜550° C., performing an ultra high vacuum chemical vapor deposition process for 1˜3 hours to deposit a Ge metal material layer, for example, pure Ge metal or Si—Ge alloy on the first opening, second opening and third opening so as to form nano-dot structure, nano-disk structure and nano-disk structure Ge metal structure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other objects, features and advantages of the present invention will become apparent to those skilled in the art upon consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings, in which: 
         FIG. 1A˜1E  is the cross section flow chart of the manufacturing method of the nano scale Ge metal structure of the embodiment of the present invention. 
         FIG. 2  is the AFM photo of the nano-dot Ge metal structure of the embodiment of the present invention. 
         FIG. 3  is the AFM photo of the nano-disk Ge metal structure of the embodiment of the present invention. 
         FIG. 4  is the AFM photo of the nano-ring Ge metal structure of the embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     In the followings, different embodiments will be used to describe the composition, arrangement and step mentioned in this invention; however, they are just examples and are not used to limit the present invention. In addition, “and/or” used in the content disclosed is just for briefing reason; “coating” or “above” description can include two situations of direct contact and non-direct contact. 
     As shown in  FIG. 1A˜1E , which is one embodiment of the present invention and is used to describe the manufacturing method of nano scale Ge metal structure of the present invention. 
     To substrate  11 , for example, Si substrate, standard semiconductor wet process will be used first to clean it, then it will be immersed in 1% HF solution to perform pre-treatment process to remove the native oxide on the surface of substrate  11  (not shown in the figure). 
     Then high temperature furnace is used to perform Atmospheric Pressure Chemical Vapor Deposition (APCVD) on substrate surface to form for example, Si02, Si3N4 and Hf02 with thickness 10˜500 nm of dielectric layer  21 ; however, the optimum thickness of dielectric layer is 100 nm as shown in  FIG. 1B . Then through photo resist coating and microlithography process, patterned photo resist layer  31  is formed on dielectric layer  21  as shown in  FIG. 1C . 
     Then E-beam Direct Writing system, for example, Leica E-beam weprint  200  equipment and Reactive Ion Etching (RIE), for example, TEL TE-5000 equipment are used to perform etching on dielectric layer  12 , then the patterned photo resist layer  31  is removed, and openings of three different dimensions A, B, C are thus formed on dielectric layer  21 , which include: a dimension in between 150˜350 nm, for example, 320 nm of first opening A; dimension in between 400˜600 nm, for example, 440 nm of second opening B; dimension in between 650˜850 nm, for example 690 nm of third opening C, as shown in  FIG. 1D . 
     At process temperature of 350˜550° C., 13 hours of Ultra-High Vacuum Chemical Vapor Deposition (UHVCVD) process is performed, the better case is 430° C. for 3 hours to deposit Ge metal material on the first opening, second opening and third opening; here the Ge metal material can be pure Ge metal (100% Ge), or metallic alloy that contains Ge, for example, the high composition SiGe alloy (Si50% Ge50%˜Si5% Ge95%, Si1-xGex). The formed metal material, due to different dimensions of the openings, will take different stresses during the deposition process; therefore, nano-dot Ge metal structure  41  will be formed at first opening A, nano-disk Ge metal structure  42  will be formed at second opening B and nano-ring Ge metal structure  43  will be formed at the third opening C. 
       FIG. 2˜4  is the measurement result using Atomic Force Microscope (AFM), on the nano-dot Ge metal structure, nano-disk Ge metal structure and nano-ring Ge metal structure formed by using the Ge metal structure manufacturing method of the present invention. The nano-dot of  FIG. 2  is of width 50 nanometer (nm) and height 21 nm; the nano-disk of  FIG. 3  is of width 309 nm and height 23 nm; and the nano-ring of  FIG. 4  is of width 286 nm and height 30 nm.