Two-Fold Reduction of Switching Current Density in Phase Change Memory Using Bi₂Te₃ Thermoelectric Interfacial Layer

Abstract

High switching current density has been a key bottleneck for phase change memory (PCM) technology. Here, we demonstrate interfacial thermoelectric heating (TEH) as a promising way of tackling this challenge. We use TEH induced by a thin Bi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Te <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> interfacial layer to demonstrate ~2× reduction of reset current density (J <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">reset</sub> ) and power (Preset) compared to control PCM devices based on Ge <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Sb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Te <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> (GST). Measurements of polarity-dependent reset current and power in well-cycled devices reveal the strong TEH caused by the Bi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Te <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> interfacial layer. The TEH origin of J <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">reset</sub> reduction is further confirmed by electrothermal simulations. Such TEH-engineered PCM devices are scalable with the bottom electrode diameter and thus could be promising for high density data storage applications.