Bumpless hybrid pixelated particle detector

A bumpless hybrid pixelated particle detector is presented. The sensor signals are transmitted from the sensor to the readout chip using capacitive (AC) coupling. In order to ease the signal transmission, simple preamplifiers are implemented in sensor pixels. The sensor chip with 100% fill-factor and in-pixel amplification is implemented in a standard high-voltage CMOS technology. High-voltage N-well/P-substrate diodes are used as sensors. Every sensor pixel contains a simple CMOS charge preamplifier, which is (using twin-well option) placed inside the cathode of the sensor diode (N-well). The output of the preamplifier is connected to an electrode implemented in the last metal layer. The input of the receiver in the readout pixel is connected to an electrode in the last metal layer, as well. When the readout chip is precisely flipped and glued onto the sensor chip, the sensor and receiver electrodes form capacitors of about 10 fF.This capacitance is large enough for the effective signal transmission. The first test results obtained with a small test matrix containing 14 × 14 pixels are presented. The pixels are 78 × 60 μm² large. Noise, threshold dispersion and radioactive source spectra have been measured.