Two dimensional, high resolution, charged-particle sensing ASICs

Describes development of a high resolution imaging XPS spectrometer. The spectrometer was to consist of four main components. A high magnification input lens; double 180° concentric hemispherical analyzers; a transfer lens between the two analyzers; and a high spatial resolution two-dimensional charge injected device (CID) detector. The input lens was to operate in the imaging mode with a magnification of at least 20. At the final exit plane there exists a spatially (and hence energy) resolved electron image, to be amplified by micro-channel plate electron multipliers and output to the CID detector. This detector has been designed to have 256×256 channels with 20 μm×20 μm pixel dimension. Thus the spatial resolution, with a times 20 magnification will be 1 μm. With this design the whole image (=250 μm) will be acquired continuously in real time without scanning the primary X-ray beam, the sample, or the ejected photoelectrons. This will allow chemical maps to be obtained at high spatial resolutions with significantly improved data collection speeds over present methods. This paper will describe the high spatial resolution, two-dimensional, charge injected, electron sensing device (CID) that is used to detect the spatially resolved image