Cubic-Structured HfLaO for the Blocking Layer of a Charge-Trap Type Flash Memory Device

Abstract

Cubic-structured HfLaO with a high kappa-value of 30-40 is used for the blocking layer in a charge-trap type memory device. Compared to an Al(2)O(3) blocking layer, the single HfLaO blocking layer shows lower leakage current, faster program speed, larger memory window, and greater robustness at high voltage, but inferior charge retention due to lower conduction band offset (CBO). When an Al(2)O(3) layer is inserted between the HfLaO and the charge trap layers, good charge retention, even at 150 degrees C, is achieved, maintaining the advantages of HfLaO. (c) 2010 The Japan Society of Applied Physics