Abstract
In recent years, demands in the semiconductor memories has increased significantly. Biomedical electronics also gradually shows its demands for non-volatile memories, such as applications in neural circuit applications. Because of the high manufacturing cost and low flexibility of embedded Flash memory process, people are seeking solutions of NVM cells realized by pure CMOS logic technologies. In this paper, an Analog Gateless OTP memory (AGO) structure has been proposed for analog storage applications. Using Resistive-Protective-Oxide (RPO) film as dielectric layer and SiN Contact Etching Stop Layer (CESL) as storage node, replacing a floating gate in a traditional flash memory. Through a design of gateless transistor with a gradually increasing channel length, the p-type channel can be partially turn on by the injected electrons from the shortest to the longest channel region gradually. Hence, continuous read current level can be stored with analog data. In addition, AGO is not only fully compatible with CMOS logic process but it also has low power consumption and high program speed of 10s per cell. Moreover, AGO has excellent NVM characteristic with large current window, good retention and disturb immunity. Therefore, the AGO technology may become a promising solution for analog data storage in the future.