Understanding the Crystallization Behavior of Surface-Oxidized GeTe Thin Films for Phase-Change Memory Application

The outstanding properties of chalcogenide phase-change materials (PCMs) led to their successful use in innovative resistive memory devices where the material is switched between its amorphous and crystalline phases. However, PCMs are easily oxidized at interfaces. Oxidation is detrimental to device performances. In particular, it reduces the data retention time since oxidized PCMs crystallize at a lower temperature than nonoxidized ones. The aim of this study is to investigate how oxidation affects the crystallization process of germanium telluride (GeTe), a prototypical PCM. By using advanced scanning transmission electron microscopy (STEM) techniques, including spatially resolved correlations between composition maps measured by energy-dispersive X-ray (EDX) spectroscopy and structural information deduced from electron diffraction patterns and high-resolution X-ray photoelectron spectroscopy, we obtained a thorough description of the local chemistry and structure of an oxidized GeTe thin film, partly c...

[1]  P. Noé,et al.  Structure and Properties of Chalcogenide Materials for PCM , 2018 .

[2]  Fast crystal nucleation induced by surface oxidation in Si-doped GeTe amorphous thin film , 2012 .

[3]  R. Liu,et al.  Multilayer SnSb4-SbSe Thin Films for Phase Change Materials Possessing Ultrafast Phase Change Speed and Enhanced Stability. , 2017, ACS applied materials & interfaces.

[4]  Christophe Vallée,et al.  Phase-change materials for non-volatile memory devices: from technological challenges to materials science issues , 2017 .

[5]  R. Berthier,et al.  In situ observation of the impact of surface oxidation on the crystallization mechanism of GeTe phase-change thin films by scanning transmission electron microscopy , 2017 .

[6]  Kumar Virwani,et al.  Voltage polarity effects in Ge2Sb2Te5-based phase change memory devices , 2011 .

[7]  Manuel Le Gallo,et al.  Monatomic phase change memory , 2018, Nature Materials.

[8]  Nicolas Bernier,et al.  Impact of interfaces on scenario of crystallization of phase change materials , 2016 .

[9]  M. Chen,et al.  Phase transformation kinetics—the role of laser power and pulse width in the phase change cycling of Te alloys , 1987 .

[10]  Matthias Wuttig,et al.  Incipient Metals: Functional Materials with a Unique Bonding Mechanism , 2017, Advanced materials.

[11]  T. Chattopadhyay,et al.  Neutron diffraction study on the structural phase transition in GeTe , 1987 .

[12]  M. Cardona,et al.  Valence bands of amorphous and crystalline GeTe determined by X‐ray and UV photoemission , 1973 .

[13]  Matthias Wuttig,et al.  The Science and Technology of Phase Change Materials , 2012 .

[14]  John G. Jones,et al.  Correlation between optical properties and chemical composition of sputter-deposited germanium oxide (GeOx) films , 2014 .

[15]  N. Yamada,et al.  Structural characteristics of GeTe-rich GeTe–Sb2Te3 pseudobinary metastable crystals , 2008 .

[16]  Q. Zheng,et al.  Nanoscale phase-change materials and devices , 2017 .

[17]  Toshio Ogino,et al.  Oxidation of Ge(100) and Ge(111) surfaces: an UPS and XPS study , 1995 .

[18]  Lada V. Yashina,et al.  X-ray photoelectron studies of clean and oxidized α-GeTe(111) surfaces , 2008 .

[19]  Daisuke Ando,et al.  Inverse Resistance Change Cr2Ge2Te6-Based PCRAM Enabling Ultralow-Energy Amorphization. , 2018, ACS Applied Materials and Interfaces.

[20]  S. Mohney,et al.  Impact of Premetallization Surface Preparation on Nickel-based Ohmic Contacts to Germanium Telluride: An X-ray Photoelectron Spectroscopic Study. , 2016, ACS applied materials & interfaces.

[21]  Dante Alighieri,et al.  Phase Change Memory: Device Physics, Reliability and Applications , 2018 .

[22]  Sylvain Maitrejean,et al.  Impact of Oxidation on Ge2Sb2Te5 and GeTe Phase-Change Properties , 2012 .