Fabrication of ALD-reinforced pixel radiation detectors on magnetic Czochralski silicon substrate

Interpixel isolation is a problem for any segmented p-type sensor. The commonly used approachs to improve the interpixel isolation is to introduce so-call p-spray and p-stop, which complicates the fabrication process and increase the likelihood of early breakdown. We used ALD (atomic layer deposition) to make alumia as interpixel dielectrics for n-implants on p-substrate. We fabricated the Medipix pixel sensors and diodes on the 150 mm p-type magnetic Czochralski silicon substrate. Process was optimized to avoid the thermal donors and maximize the negative charges existing at the interface between silicon and alumina. Preliminary results show a good uniformity across the wafer. Medipix pixel sensors are assembled on the Timpeix readout chips by low temperatue flip-chip bonding. Detectors are characterized with X-rays and radioactive sources and the spectroscopic results will be presented.