p/n/n Cz-Si detectors processed on p-type Boron-doped substrates with thermal donor induced space charge sign inversion

We have processed pad detectors on high-resistivity p-type Cz-Si wafers. The resistivity of the boron-doped silicon is approximately 1.8 k Omega cm after the crystal growth. The detector processing was carried out using the common procedure for standard n-type wafers, to produce p(+)/p/p(-)/n(+) detector structures. During the last process step, i.e., sintering of aluminum electrode, the p-type bulk was turned to n-type through generation of thermal donors (TD). This way, high oxygen concentration p(+)/n(-)/n(+) Cz-Si detectors were realized with low temperature process. The full depletion voltage of detectors could be tailored between wide range front 30 V up to close 1000 V by changing heat treatment at 400 degrees C-450 degrees C duration from 20 to 80 min. The space charge sign inversion (SCSI) in the TD generated devices (from p(+)/p(-)/n(+) to p(+)/n(-) (inverted)/n(+)) has been verified by transient current technique measurements. The detectors show very small increase of full depletion voltage after irradiations with 24 GeV/c protons up to 5 * 10(14) p/cm(2).