Position-Sensitive Semiconductor Particle Detectors Fabricated by Ion Implantation

The advantages and problems associated with the use of ion implantation for the fabrication of position-sensitive particle detectors are discussed. Analysis of the noise and pulse risetime properties of such devices shows the desirability of using a high sheet resistance in the distributing resistive layer for optimum position resolution while restricting the RC of the detector to values approximately equal to the clipping times used in the measuring circuits in order to obtain good position linearity. From both detector noise and pulse rise-time considerations it is found desirable to use equal pulse shaping in the energy and the position signal measuring systems. Detectors were made by implantation of 60 keV boron and phosphorus ions into 4000 ohm-cm n-type silicon. Representative results are shown for a 4×32 mm2 one dimensional detector which shows integral and differential position nonlinearity of less than one percent and position resolution of less than 0.2 mm. Extension to one dimensional detectors up to 50 mm and to 10×10mm two dimensional detectors is discussed.