A fast read retry method for 3D NAND flash memories using novel valley search algorithm

Abstract

Read retry is one of the most effective methods to reduce retention errors caused by charge loss. A novel valley search algorithm for fast read retry method is proposed in this paper, which can reduce read operations to two times from at least three by conventional valley search algorithm [1, 8]. Experimental results illustrate that raw bit error rate (RBER) after read retry is reduced to 0.0344% using the novel valley search algorithm, which is within 4.41% of BCH(9088,8192,64) error correcting code (ECC) [2, 3] error correction capability.