NONCONTACT EVALUATION OF CAPACITANCE DISK MEMORY WITH FERROELECTRIC SEMICONDUCTOR STRUCTURE

Noncontact evaluation of capacitance disk memory with ferroelectric se miconductor (FS) structure was performed in order to avoid Near of the head and medium. Head-medium spacing was actively controlled using di fferential capacitance between the head and medium as the active feedb ack signal. Using this system, head-medium spacing could be stably con trolled to be as low as 30 nm, which is less than that of a magnetic h ard disk. Ferroelectric film of the medium was poled, which correspond ed to recording in memory application, while head-medium spacing was k ept constant using the active spacing control system. Change in capaci tance due to poling direction, which corresponded to the reproduction signal in memory application, could be observed at the spacing below 1 00 nm. As a result, we confirmed that ferroelectric/semiconductor disk memory could function without head-medium contact. The surface image was also obtained using the capacitance signal while differential capa citance was kept constant.