N2 gas flow rate dependence on the high-k LaB x N y thin film characteristics formed by RF sputtering for floating-gate memory applications

Abstract

In this paper, the N2 gas flow rate dependence on the high-k LaB x N y thin film characteristics formed by RF sputtering for floating-gate memory applications was investigated. The N2 gas flow rate during the sputtering for the LaB x N y insulating layer was increased from 3 to 9 sccm with the Ar of 10 sccm for N-doped LaB6 (Metal: M)/LaB x N y (Insulator: I)/p-Si(100). Then, the N-doped LaB6/LaB x N y /N-doped LaB6/LaB x N y /p-Si(100) MIMIS diode was fabricated with LaB x N y tunnel layer and block layer formed by Ar/N2 gas flow ratio of 10/7 sccm. The equivalent oxide thickness (EOT) was decreased from 7 to 5.5 nm by increasing the N2 gas flow rate from 3 to 7 sccm. On the other hand, the LaB x N y insulating layer formed by N2 gas flow rate of 9 sccm showed EOT of 8.2 nm with crystallization. Furthermore, the memory window of 0.4 V was obtained for the MIMIS floating-gate structure utilizing the N-doped LaB6/LaB x N y stacked layer.