Effects of Nitrogen Addition on the Properties of Ge-Doped SbTe Phase Change Memory Material

Abstract

Reduction of reset current and suppression of thermal interference between memory cells are considered to pose major technical challenges to the development of successful high-density phase-change memory devices. To overcome these challenges, a memory device may need a phase-change material featuring a low melting temperature combined with a high crystallization temperature. In this report, we propose a candidate material system, consisting of Ge-doped SbTe for a base material and nitrogen for a complementary property-modifier. Nitrogen-added Ge-doped SbTe materials were characterized to show that, with an increase in nitrogen content; melting temperature remains nearly constant and lower than that of Ge2Sb2Te5; the crystallization temperature increases; and the electrical resistivities increase for as-deposited and annealed materials as well. In addition, the proposed materials were found to have excellent scaling characteristics in terms of crystallization speed. The observed property changes are discussed in relation to growth-dominant crystallization and the varying mode of nitrogen accommodation between intra-and inter-granular modes, and through comparison with a case of N-doped Ge2Sb2Te5 material.