Abstract: An LED and its fabrication method are disclosed. The LED includes: a sapphire substrate (200); an epitaxial layer (220), an active layer (230) and a capping layer (240) arranged on the sapphire substrate (200) in sequence; wherein a plurality of bifocal microlens structures (201) are formed on the surface of the sapphire substrate (200) close to the epitaxial layer (220). The bifocal microlens structures (201) can increase the light reflected by the sapphire substrate (200), raising the external quantum efficiency of the LED, thus increasing the light utilization rate of the LED. Furthermore, the bifocal microlens structures (201) can improve the lattice matching between the sapphire substrate (200) and other films, reducing the crystal defects in the film formed on the sapphire substrate (200) and increasing the internal quantum efficiency of the LED.

Abstract: A method for analyzing a sample for the manufacture of integrated circuits, e.g. MOS transistors, application specific integrated circuits, memory devices, microprocessors, system on a chip. The method includes providing an integrated circuit chip, which has a surface area with at least one region of interest, e.g., bond pad. The method includes covering a first portion of the surface area including the region of interest using a blocking material. The method also forms a metal layer on a second portion of the surface area, while the blocking material protects the first portion. The method removes the blocking material to expose the first portion of the surface area including the region of interest. The method also subjects the metal layer to a voltage differential to draw away one or more charged particles from the first portion of the surface area. The method also subjects the surface area including the region of interest to spectrometer analysis.