Point defects and nanoclusters in irradiated high-purity silicon

The proposal addresses some fundamental scientific issues of key relevance for advanced particle detectors based on high-purity low-doped silicon. Fabrication of such devices is a core activity within Micro(Nano)-System-Technology (M(N)ST) and a vital par t of the international 'MST-profile' of Norway. The most critical aspect of these detectors is the formation of electrically active defects in the Si-material when exposed to particle irradiation. Defects in high-purity and low-doped Si are scarcely studied and poorly understood, and in this project we will investigate the formation mechanisms, annealing kinetics and structural symmetry of the major irradiation-induced point defects and higher-orde r complexes (nanoclusters) in such Si-materials. This will give imperative knowledge of how to 'engineer' Si-wafers in order to obtain detectors with the utmost radiation hardness and it will also provide input to computer modeling of the defect character istics. Excellent experimental facilities exist (or will exist) for processing and characterization of the Si-samples. Here, the new Microsystem Research Laboratory (MRL) in Oslo, Gaustabekkdalen, will be an invaluable asset. Further, the project involves extensi ve international collaboration with several leading groups in the field of Si particle detectors and irradiation-induced defects, and it is conducted in close association with one Nordic and two European networks.