CERN Accelerating science

Preprint
Report number	CERN-ALI-98-24 ; CERN-ALICE-PUB-98-24
Title	Radiation Tolerance of Single-Sided Microstrip Detector with $Si_{3}N_{4}$ Insulator
Author(s)	Maslov, N I ; Kulibaba, V ; Potin, S ; Starodubtsev, A ; Kuijer, P G ; De Haas, A P ; Perevertailo, V
Affiliation	(CERN) ; (NSC KhIPT Kharkov) ; (Univ. Utrecht) ; (SPA Detector Kiev)
Publication	1998
Imprint	4 Nov 1998
Number of pages	mult.
Note	Conference Proceedings of the 6th International Conference on Advanced Technology and Particle Physics, Villa Olmo, Como, Italy, 5-9 October 1998
Presented at	6th International Conference on Advanced Technology and Particle Physics : ICATPP-6, Como, Italy, 5 - 9 Oct 1998
Subject category	Detectors and Experimental Techniques
Accelerator/Facility, Experiment	CERN LHC ; ALICE
Keywords	ITS ; capacitors ; insulate ; irradiation ; leakage
Abstract	The ALICE Collaboration is investigating the radiation tolerance and operation of silicon microstrip detectors for the inner tracking system. Detectors with and without an additional layer of Si3N4 insulator were made in one set, using the same thickness of SiO2 insulator. Measurements were made on both types of detectors after irradiation with 20 MeV electrons, using doses up to 2Mrad. The additional Si3N4 layer allows a coupling capacitor breakdown voltage larger than 100 V and capacitor yield larger than 99 percent. However, the leakage current for detectors with double layer insulator is about 20 nA per strip while the leakage current for the single layer SiO2 insulated detectors is only 0.5 nA. The 20 nA leakage current leads to 450 electrons noise when the ALICE 128C electronics with a peaking time of 1.4 microseconds is used. At a 1 nA leakage current the noise is 100 electrons. The ENC for an input capacitance of 5 pF is 300 electrons. Since all detectors show an increased leakage current after irradiation, the difference between the single and duoble layer insulation detectors becomes negligible when doses of the order of several hundreds of krad are applied.
Copyright/License	Preprint: (License: CC-BY-4.0)