Impact of Low-Dose Electron Irradiation on the Charge Collection of n+p Silicon Strip Sensors

6 Jun 2014, 15:00
20m
Berlagezaal (Beurs van Berlage)

Berlagezaal

Beurs van Berlage

Oral Sensors: 1b) Semiconductor Detectors I.b Semiconductors

Speaker

Mr Robert Klanner (University of Hamburg)

Description

The response of p+n strip sensors to electrons from a 90Sr source and focussed laser light with different wave lengths was measured using the ALiBaVa read-out system. The measurements were performed over a period of several weeks, during which a number of operating conditions were varied. The sensors were fabricated by Hamamatsu on 200 µm thick float-zone silicon. Their pitch is 80 µm, and both p-stop and p-spray isolation of the p+n strips were studied. The electrons from the 90Sr source were collimated to a spot with a full-width-at-half maximum of 1.8 mm at the sensor and the dose rate at the maximum in the SiO2 was about 0.6 mGy/s. The estimated dose at the end of the measurements was about 1 kGy in SiO2. In addition, test structures (pad diodes, MOS capacitors with and without p-stop and p-spray implants, and gate-controlled diodes) fabricated together with the sensors, were investigated for X-ray doses of up to 1 kGy in SiO2 in order to determine technological parameters and their dependencies on X-ray dose. As function of irradiation time with the 90Sr source significant changes in charge collection and charge sharing are observed. Annealing studies with temperatures up to 80°C have shown that the observed changes are only partially reversed. The observations are qualitatively explained with the help of TCAD simulations. The relevance of the measurements for the design and the use of p+n strip sensors in different radiation environments are discussed.

Primary author

Mr Robert Klanner (University of Hamburg)

Presentation Materials