단차형상산화막을 이용한 나노 플로팅 게이트 메모리의 멀티레벨 특성

Abstract

In recent decades, memory device technology has advanced through active research and the development of innovative technologies. Single transistor-based flash memory device is one of the most widely used forms of memory devices because of simple structure and feasible scaling. A nano floating gate memory (NFGM) device is a flash memory device that uses nanocrystals as a charge-trapping element. Nanocrystals have advantages over other memory devices that rely on other methods such as discontinuous trap sites and controllable trap levels. Using these methods, there is a need to develop functional memory devices that would solve current physical and electrical issues and ultimately replace the current flash memory.

In this study, Al2O3 step-shape control oxide NFGM multi level characteristics were implemented. Furthermore, to analyze the effect on memory, metallic Au and Ag nanocrystals using the device’s storage characteristics were carried out. The formation of nanocrystals was controlled by thickness of wetting layer and post-annealing process. Al2O3 was chosen as control oxide based on tunneling oxide and control oxide dielectric constant related theory. Au and Ag nanocrystal embedded NFGM MOSCAP devices were analyzed by flatband voltage shift and retention test according to their work function. For implementation of Al2O3 NFGM multi level electric charge storage, Al2O3 control oxide layer were partially etched 30nm from 60nm and the result shows that multi level characteristics and memory windows were about 4V, 8V, respectively.

Using analytical methods and the results applied to multi level NFGM using Al2O3 as control oxide, superior properties in the non-volatile multi level NFGM characteristics are expected to be achieved.