Bulk fin-type field-effect transistor-based capacitorless dynamic random-access memory with strong resistance to geometrical variations

Abstract

In this study, a bulk fin-type field-effect transistor (FinFET)–based capacitorless one-transistor dynamic random-access memory (1T-DRAM) was proposed. The fabrication process of the proposed 1T-DRAM was similar to that of a typical junctionless bulk FinFETs, except that the p-type doped body fin region operated as a charge storage region. The effects of the geometrical variations, such as the fin angle (θfin) variation and line edge roughness (LER), which are inevitable in fabrication, on the transfer characteristics and memory performance of the proposed 1T-DRAM were studied. θfin was varied from 90° to 80°, and 200 samples with the LER were analyzed. Results revealed that the transfer characteristics and memory performance were affected by geometrical variations. However, the proposed 1T-DRAM exhibited an excellent retention time in all cases because the charge storage region was separated from the region of operation.