Speaker
Description
A monolithic pixel sensor named HVMAPS25 has been implemented in a 180nm HVCMOS technology. The pixel size is 25µm x 35µm. The pixel electronics contains a fast and low power charge sensitive amplifier, comparator, threshold tune DAC and a digital circuit that measure the arrival time of the hit with 10 bit resolution, <10ns bin width, and the amplitude (ToT) with 6 bit resolution.
The sensor is implemented in a commercial process of TSI Semiconductors on 200Ωcm substrate. Deep p-well has been used for isolation of the pixel electronic from the sensor substrate. The design and measurement will be presented.
Summary (500 words)
The monolithic particle pixel sensor HVMAPS25 has been implemented in the 180nm HVCMOS technology of TSI Semiconductors. The signal charge collection electrodes are small n-wells (2 µm x 4µm) embedded in the high resistivity p-type substrate. The sensor n-wells are AC-coupled to the amplifiers and the can be biased with 10V with respect to the p-substrate. In this way the sensor substrate is partially depleted.
The pixel size is 25 µm x 35 µm. The pixel electronics (NMOS and PMOS transistors) are placed in shallow p- and n-wells and these wells are embedded in the deep p-well used as potential barrier for signal electrons. In this way, we prevent signal loss that could happen if signal electrons drift towards shallow n-wells of PMOS transistors.
The pixel electronics contains a fast and low power charge sensitive amplifier, comparator, threshold tune DAC and a digital circuit that measures the arrival time of the hit with 10 bit resolution and the amplitude (time over threshold) with six bit resolution. Time resolution better than 10ns can be achieved. The current < 1µm for the pixel amplifier.
The sensor could be applied in a vertex detector of some future experiment such as CLIC.
Digital periphery, placed at the bottom of the chip, consist of two blocks, one is the synthesized digital part RCU.
We have performed tests of the overall functionality, measurements of the amplitude response, threshold scan and threshold tune measurements and tests with radioactive sources. The attached figure illustrates the measurement of the digitized amplitude (time of the threshold) versus injected test charge. More measurements and more design details will be presented.
