Investigation of recombination characteristics in si particle detector structures and si substrates

Silicon is the most widely used semiconductor in electronics. Silicon based particle detectors are widely used in high energy and nuclear physics experiments. Standard large-area particle detectors have relatively wide inactive peripheries (~1 mm), which accounts for a large part of the entire detector area. In order to increase the part of the active area of the detector, it is necessary to remove the inactive areas. Scribe-cleave-passivate (SCP) method is used for this purpose, when the inactive area of the detector is mechanically broken off along the line that is incised with a laser. In order to reduce the leakage surface leakage current, the edges of the detector are then passivated using low temperature methods. The surface recombination velocity determines the efficiency of the passivation and correlates with the surface leakage current. Therefore, in order to develop reliable technologies for the production of large active area particle detectors it is necessary to take control of the surface recombination velocity and the durability of the passivation layers. In recent years the formation of epitaxial GaN layers on Si substrates for various applications has gained considerable interest due to the relatively low cost of Si substrates. In order to obtain high-quality GaN layers, the AlN buffer layer is deposited on Si beforehand. However, electrically active defects formed on the AlN/Si interface and Si surface may determine the functionality of the GaN based devices. In order to produce high-quality and reliable devices, it is important to investigate the electrically active defects that are formed on the Si substrate and the resulting changes in recombination characteristics. In this work series of Si-based unpassivated and passivated using different methods particle detector structures and AlN/AlGaN/GaN Si substrates were investigated. In order to evaluate the radiation influence on the recombination characteristics of the detector structures, some of the samples were irradiated with protons with different fluences. The recombination characteristics of the samples have been examined using contactless microwave probed photoconductivity transient (MW-PC) method. The impurities present in Si substrates were identified and their concentrations evaluated by deep level transient spectroscopy (DLTS) method. An analysis of different methods of surface passivation efficiency, degradation, radiation influence on recombination characteristics and DLTS spectra of Si detector structures and Si substrates has been presented