Particle detectors based on semi-insulating silicon carbide

Particle detectors were made using semi-insulating 4H-SiC as the detection medium. Devices produced with this material have the possibility of being e xtremely radiation hard. For the purposes of building radiation hard detect ors, the parameters of interest are the large band gap and low intrinsic ca rrier density which implies low leakage currents, the large resistivity tha t allows ohmic contacts to be used to sense the charge created during ionis ation, the large breakdown voltage that gives stable operation, and the lar ge cohesive energy and tightly bound structure which imply good radiation r esistance. The investigated photoconductivity detectors are formed by ohmic contacts (Al) on the front- and back-side of a 310 mu m thick semi-insulat ing 4H-SiC substrate from Cree. These structures of contacts are ranging fr om 1 - 3 mm in diameter and have a guard ring structure to prevent edge lea kage currents. From the I-V characteristic a substrate resistivity of 5.1.1 0(10) Omega cm was determined. The detectors respond to beta-particles simi lar as detectors made of diamond. Signal heights of about 2000 e(-) were ac hieved for quasi minimum ionising electrons. First radiation hardness tests shows an increase of the substrate resistivity by a factor three after a p roton (3 GeV) fluence of 4.16.10(14) cm(-2) and a reduction of the signal h eight of about 23%. The results indicate the feasibility of using silicon c arbide as detection medium for particle detectors. Future developments of S iC-detectors with applications in particle physics experiments and other fi elds are discussed.