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Direct detection of low-energy electrons (500–2000 eV) with a novel back-thinned CMOS active pixel sensor (APS) is reported in this paper. The sensor was installed in a JEOL 6400F scanning electron microscope to quantitatively test its linearity and spatial resolution by a focused electron beam. The obtained results show good linearity at electron beam energy values from 500 to 2000 eV. The full-width at half-maximum spatial resolution was around 2 pixels, a limit set by charge diffusion in the epilayer. These results show that this CMOS APS sensor is appropriate for low-energy electron detection providing the benefits of direct detection for many applications. [ABSTRACT FROM AUTHOR]

We present a novel complementary metal–oxide–semiconductor (CMOS) active-pixel sensor imager that incorporates different reset schemes to achieve lower reset noise levels. The sensor, eLeNA, features a 448 \times 512 array with a pixel pitch of 15 \mu\m, fabricated using a 0.18- \mu\m CMOS process. Fourteen sections and five different reset methods were employed. Without using pinned diodes, we implanted structures for correlated double sampling. A noise of 6 \e- is measured with a conversion gain of 49 \mu\V/e-. We will discuss various applications for the reset method that achieved the best overall performance, considering leakage current and read noise. [ABSTRACT FROM PUBLISHER]

Abstract: Stitched, large area, complementary metal-oxide-semiconductor (CMOS), active pixel sensors (APS) show promises for X-ray imaging applications. In this paper we present an investigation of the effects of stitching on uniformity of sensor response for an experimental APS. The sensor, known as LAS (large area sensor), was made by reticular stitching onto a single silicon wafer of a 5×5 array of regions consisting of 270×270 pixels with 40μm pixel pitch, to yield 1350×1350 pixels and an imaging area of 54×54mm. Data acquired from two different sensors of the same type were filtered to remove spiking pixels and electromagnetic interference (EMI). The non-linear compensation (NLC) technique for CMOS sensor analysis was used to determine the variation in gain, read noise, full well capacity and dynamic range between stitched regions. Variations across stitched regions were analysed using profiles, analysis of pixel variations at stitch boundaries and using a measurement of non-uniformity within a stitched region. The results showed that non-uniformity variations were present, which increased with signal (1.5–3.5% at dark signal, rising to 3–8%). However, these were found to be smaller than variations caused by differences in readout electronics, particularly at low signal levels. The results suggest these variations should be correctable using standard calibration methods. [ABSTRACT FROM AUTHOR]