Two-Fold Reduction of Switching Current Density in Phase Change Memory Using Bi₂Te₃ Thermoelectric Interfacial Layer
Asir Intisar Khan, Heungdong Kwon, Raisul Islam, Christopher Perez, Michelle Chen, Mehdi Asheghi, Kenneth E. Goodson, H.‐S. Philip Wong, Eric Pop
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.