A high performance phase change memory with fast switching speed and high temperature retention by engineering the Ge<inf>x</inf>Sb<inf>y</inf>Te<inf>z</inf> phase change material

Abstract

Phase change memory has long suffered from conflicting material properties between switching speed and thermal stability. This study explores the engineering of GeSbTe ternary alloys along an isoelectronic tie line and the Ge/Sb <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> Te <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> tie line with the hope of finding a high performance material. Our efforts resulted in a new material that considerably outperforms the conventional GST-225. The switching speed is similar to undoped GST-225, with ∼ 30% lower reset current, and nearly 100°C higher T <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</inf> , thus much better thermal stability. The promising properties of this new material are demonstrated in a 128Mb chip and tested both at wafer level and as packaged dies. These devices showed 1E8 cycling endurance and withstood 190 °C testing.