Enabling Universal Memory by Overcoming the Contradictory Speed and Stability Nature of Phase-Change Materials

The quest for universal memory is driving the rapid development of memories with superior all-round capabilities in non-volatility, high speed, high endurance and low power. Phase-change materials are highly promising in this respect. However, their contradictory speed and stability properties present a key challenge towards this ambition. We reveal that as the device size decreases, the phase-change mechanism changes from the material inherent crystallization mechanism (either nucleation- or growth-dominated), to the hetero-crystallization mechanism, which resulted in a significant increase in PCRAM speeds. Reducing the grain size can further increase the speed of phase-change. Such grain size effect on speed becomes increasingly significant at smaller device sizes. Together with the nano-thermal and electrical effects, fast phase-change, good stability and high endurance can be achieved. These findings lead to a feasible solution to achieve a universal memory.

[1]  H. Shieh,et al.  Enhancement of Data Transfer Rate of Phase Change Optical Disk by Doping Nitrogen in Ge–In–Sb–Te Recording Layer , 2004 .

[2]  M. Wuttig,et al.  Atomic force microscopy measurements of crystal nucleation and growth rates in thin films of amorphous Te alloys , 2004 .

[3]  K. Kelton.  Crystal Nucleation in Liquids and Glasses , 1991 .

[4]  Roland E. Allen,et al.  Response of GaAs to fast intense laser pulses , 1998 .

[5]  M Bernasconi,et al.  First-principles study of nitrogen doping in cubic and amorphous Ge2Sb2Te5 , 2011, Journal of physics. Condensed matter : an Institute of Physics journal.

[6]  Norikazu Ohshima,et al.  Crystallization of germanium–antimony–tellurium amorphous thin film sandwiched between various dielectric protective films , 1996 .

[7]  N. Yamada,et al.  Rapid‐phase transitions of GeTe‐Sb2Te3 pseudobinary amorphous thin films for an optical disk memory , 1991 .

[8]  Guo-Fu Zhou,et al.  Materials aspects in phase change optical recording , 2001 .

[9]  Y. Ha,et al.  Observation of molecular nitrogen in N-doped Ge2Sb2Te5 , 2006 .

[10]  Se-Ho Lee,et al.  Highly scalable non-volatile and ultra-low-power phase-change nanowire memory. , 2007, Nature nanotechnology.

[11]  W. G. Perdok,et al.  On the relations between structure and morphology of crystals. I , 1955 .

[12]  A. Pirovano,et al.  Scaling analysis of phase-change memory technology , 2003, IEEE International Electron Devices Meeting 2003.

[13]  Luping Shi,et al.  Ultrafast switching in nanoscale phase-change random access memory with superlattice-like structures , 2011, Nanotechnology.

[14]  A. Needleman.  An analysis of decohesion along an imperfect interface , 1990 .

[15]  J. Tominaga,et al.  Understanding the phase-change mechanism of rewritable optical media , 2004, Nature materials.

[16]  Bingchu Cai,et al.  Nitrogen-doped Ge2Sb2Te5 films for nonvolatile memory , 2005 .

[17]  Wei Chong,et al.  Thickness Dependent Nano-Crystallization in Ge2Sb2Te5 Films and Its Effect on Devices , 2006 .

[18]  M. Kund,et al.  Nanosecond switching in GeTe phase change memory cells , 2009 .

[19]  Myong R. Kim,et al.  Crystallization behavior of sputter-deposited amorphous Ge2Sb2Te5 thin films , 1999 .

[20]  Simone Raoux,et al.  Crystallization properties of ultrathin phase change films , 2008 .

[21]  D. Choi,et al.  Electrical properties and crystal structures of nitrogen-doped Ge2Sb2Te5 thin film for phase change memory , 2004 .

[22]  Change in electrical resistance and thermal stability of nitrogen incorporated Ge2Sb2Te5 films , 2007 .

[23]  Rudd,et al.  Binary-encounter-dipole model for electron-impact ionization. , 1994, Physical review. A, Atomic, molecular, and optical physics.

[24]  Noboru Yamada,et al.  Nitrogen Doping Effect on Phase Change Optical Disks , 1998 .

[25]  Yihong Wu,et al.  Fast phase transitions induced by picosecond electrical pulses on phase change memory cells , 2008 .

[26]  Alexander V. Kolobov.  Information storage: around the phase-change cycle. , 2008, Nature materials.

[27]  Ross,et al.  Femtosecond dynamics of multielectron dissociative ionization by use of a picosecond laser. , 1987, Physical review letters.

[28]  T. Hsieh,et al.  Phase transition behaviors of Mo- and nitrogen-doped Ge2Sb2Te5 thin films investigated by in situ electrical measurements , 2009 .

[29]  D. Adler,et al.  Threshold Switching in Chalcogenide-Glass Thin Films , 1980 .

[30]  Min-Gon Kim,et al.  Ge nitride formation in N-doped amorphous Ge2Sb2Te5 , 2007 .

[31]  Banfield,et al.  Imperfect oriented attachment: dislocation generation in defect-free nanocrystals , 1998, Science.

[32]  J. H. Coombs,et al.  Laser‐induced crystallization phenomena in GeTe‐based alloys. II. Composition dependence of nucleation and growth , 1995 .

[33]  Byung Joon Choi,et al.  Phase transformation behaviors of SiO2 doped Ge2Sb2Te5 films for application in phase change random access memory , 2008 .

[34]  S. K. Sundaram,et al.  Inducing and probing non-thermal transitions in semiconductors using femtosecond laser pulses , 2002, Nature materials.

[35]  Erik Jan Marinissen,et al.  Challenges in embedded memory design and test , 2005, Design, Automation and Test in Europe.

[36]  A. Pirovano,et al.  Electronic switching effect in phase-change memory cells , 2002, Digest. International Electron Devices Meeting,.

[37]  Pal Molian,et al.  Coulomb explosion-induced formation of highly oriented nanoparticles on thin films of 3C–SiC by the femtosecond pulsed laser , 2004 .

[38]  S. Lai,et al.  OUM - A 180 nm nonvolatile memory cell element technology for stand alone and embedded applications , 2001, International Electron Devices Meeting. Technical Digest (Cat. No.01CH37224).

[39]  S. Ovshinsky.  Reversible Electrical Switching Phenomena in Disordered Structures , 1968 .