Abstract: An avalanche photodiode includes a GeOI substrate; an I—Ge absorption layer configured to absorb an optical signal and generate a photo-generated carrier; a first p-type SiGe layer, a second p-type SiGe layer, a first SiGe layer, and a second SiGe layer, where a Si content in any one of the SiGe layers is less than or equal to 20%; a first SiO2 oxidation layer and a second SiO2 oxidation layer; a first taper type silicon Si waveguide layer and a second taper type silicon Si waveguide layer; a heavily-doped n-type silicon Si multiplication layer; and anode electrodes and a cathode electrode.

Abstract: A high efficiency multiring solar cell (MRSC) system, including a number of single-junction solar cells and utilizing a novel multiring architecture is disclosed. Sunlight from the solar concentrator illuminates a double cone prism to create spatially separated spectral bands. Projection of the spectral bands on working surfaces of solar cells creates a sequence of spatially separated spectral rings, where rings corresponding to the spectral bands with longer wavelengths are enclosed by the rings corresponding to shorter wavelengths. The number of solar cells and their shape corresponds to the number and the shape of the respective spectral rings. Each solar cell is optimized for efficiently converting the sunlight from the corresponding spectral band. A corresponding method of forming solar cells and converting sunlight into electricity are also provided.

Abstract: A method for preparing TEM sample, comprising the following steps: providing a sample with two pits and a failure region between the two pits, the failure region comprising a semiconductor device; milling the first surface of the failure region, till the cross section of the semiconductor device is exposed; etching the first surface of the failure region; cleaning the sample; milling the second surface of the failure region, till the failure region can be passed by electron beam. A sample can be prepared for a high resolution TEM through above steps. When the sample is observed, it is easy to distinguish the lightly doped drain, source/drain regions from the silicon substrate and observe the pattern and defects in the lightly doped drain, source/drain regions clearly; in addition, it is easy to distinguish the BPSG from the non-doped silicon dioxide in the failure region.

Abstract: A method for preparing TEM sample, comprising the following steps: providing a sample with two pits and a failure region between the two pits, the failure region comprising a semiconductor device; milling the first surface of the failure region, till the cross section of the semiconductor device is exposed; etching the first surface of the failure region; cleaning the sample; milling the second surface of the failure region, till the failure region can be passed by electron beam. A sample can be prepared for a high resolution TEM through above steps. When the sample is observed, it is easy to distinguish the lightly doped drain, source/drain regions from the silicon substrate and observe the pattern and defects in the lightly doped drain, source/drain regions clearly; in addition, it is easy to distinguish the BPSG from the non-doped silicon dioxide in the failure region.