Improved Performance of Phase Change Memory Cell with Strontium Titanate and Barium Titanate Buffer Layer

Abstract

T-shape phase change memory (PCM) cells with SrTiO3 (STO) or BaTiO3 (BTO) buffer layer were fabricated and characterized. Compared to the conventional T-shape PCM cell, the reset voltages using BTO and STO as buffer layer with pulse width 50 ns were reduced by 28 and 38%, respectively. According to the result of the thermal resistance calculation, the overall thermal resistance of PCM cell increases remarkably by inserting BTO (STO) layer, which can efficiently reduce the dissipated power, resulting in the reduced reset voltage. Combined with the resistance–voltage characteristics of the PCM cell, the current–voltage characteristics of BTO and STO thin films indicate that BTO thin film is more suitable than STO thin film as a buffer layer. The theoretical thermal simulation for reset process is applied to understand the effect of buffer layer on improving the performance of the PCM cell.