High Mobility and GIDL Erase-Compatible Characteristics in Hybrid Channel (Poly-Si/IGO) for Ultrahigh 3D NAND Flash Memory Applications

In this paper, we propose a hybrid channel (HC) structure in which the poly-Si and indium gallium oxide (IGO) channels coexist to achieve high mobility and gate-induced-drain-leakage (GIDL) erase-compatible characteristics for 3D NAND flash memory applications. The high mobility is achieved through the additional formation of oxygen vacancies at the interface between poly-Si and IGO channels. These additional vacancies increase electron carrier generation, thereby improving the field-effect mobility through the percolation effect. In addition, the GIDL erase operation is achieved by leveraging the poly-Si channel characteristics. Based on the measured I–V curve of the fabricated field-effect transistor devices, we obtained the high mobility of the IGO channel (63.78 cm–2/V·s) and the comparable GIDL current characteristics of the poly-Si channel (15 nA). Furthermore, using Technology Computer Aided Design (TCAD) simulation, we verified the GIDL erase operation of the proposed HC structure in 3D NAND flash memory applications. Therefore, these experimental and simulation results demonstrate that the proposed HC structure is suitable for ultrahigh 3D NAND flash memory applications requiring high mobility and GIDL erase-compatible characteristics.