Method for producing single crystal, and needle-like single crystal

A substrate having at least one single crystal pin thereon, said substrate having a surface comprising:

• (1) a single crystal material or layer, said single crystal material or layer having been etched to a depth of from 1 to 100 microns around a desired metal pattern formed on the surface of said single crystal material or layer prior to etching and prior to forming a single crystal pin thereon,
• said single crystal material or layer having a thickness of at least 3 microns, said material or layer having a first surface on which said desired metal pattern was formed and a second surface lower than said first surface, said second surface being formed by etching said single crystal material or layer around said desired metal pattern to the depth of said second surface;
• (2) at least one etched tapered single crystal base portion extending from said first surface of said single crystal material or layer to said second surface, said tapered single crystal base portion being located at a position beneath said metal of said desired pattern, and having been formed by etching said single crystal material or layer at portions not protected by said metal;
• said tapered single crystal base portion having (i) a proximal end located at said second surface and (ii) a distal end located at said first surface, the diameter of the proximal end at said second surface being larger than the diameter (d) of said distal end at said first surface, such that said base portion is tapered in shape with its smaller diameter being at the first surface of said single crystal material or layer;
• and
• (3) a vertical single crystal pin which is in contact with and has been grown on and at the distal end of said tapered single crystal base portion at locations of said single crystal material or layer where said desired metal pattern was formed, said vertical pin having an end distal from the distal end of said tapered single crystal base portion, the axis of said vertical single crystal pin being perpendicular to said single crystal layer or forming an angle .theta. with a line perpendicular to said single crystal material or layer, said angle .theta. being not more than 20.degree..