STUDY OF BASIC MECHANISMS OF SEMICONDUCTOR-DEVICES USING ION-BEAM-INDUCED CHARGE (IBIC) COLLECTION

A change of wave form of current transients induced by a single heavy ion was investigated around a pn junction with 8 mu m width and 10 mu m length as a function of the ion incident position. Three pn junction s were made on a 3 mu m thick Si epilayer (1x10(16)/cm(3)) grown on Si substrate and were in a line along an aluminum electrode with 10 mu m spacing between the adjacent junctions. The elements of a pn junction array were irradiated with a 1 mu m diameter 15 MeV C+ heavy ion micr obeam spacing steps by 3 mu m. At a bias voltage of -10 V, 148, 91, an d 54 fC were collected at the pn junction center, and at 3 mu m and 4 mu m from the edge of the electrode, respectively. Internal device str ucture was examined by IBIC (ion beam induced current) method by using a 2 MeV He+ ion microbeam. From the IBIC spectrum and the IBIC image, the charge collected from the open space by the diffusion process was observed in addition to the charge collected from the depletion layer of the pn junction.