Low noise Junction Field Effect Transistors in a silicon radiation detector technology

We report on n-channel Junction Field Effect Transistors fabricated on high resistivity silicon by means of a specially tailored radiation detector technology. This research activity is being carried out in the framework of a project aiming at the integration of read-out circuits in the same detector substrate. Possible applications are in the field of medical/industrial imaging, space and high energy physics experiments. The pre-existent fabrication process has been modified in several respects to enhance the device noise behavior. In particular, the new process features a high-energy (1 MeV) Boron implantation to obtain a deep p-well which ensures an effective isolation of the transistor from the substrate and a strong modulating effect on the current. Selected results from the experimental characterization of transistors and charge sensitive amplifiers are presented, showing a sizable enhancement in the noise performance with respect to previously available devices. Index Terms--Charge sensitive amplifiers, fabrication technology, junction field effect transistors, noise, radiation detectors.