Enhanced non-volatile memory characteristics with quattro-layer graphene nanoplatelets vs. 2.85-nm Si nanoparticles with asymmetric Al2O3/HfO2 tunnel oxide

In this work, we demonstrate a non-volatile metal-oxide semiconductor (MOS) memory with Quattro-layer graphene nanoplatelets as charge storage layer with asymmetric Al2O3/HfO2 tunnel oxide and we compare it to the same memory structure with 2.85-nm Si nanoparticles charge trapping layer. The results show that graphene nanoplatelets with Al2O3/HfO2 tunnel oxide allow for larger memory windows at the same operating voltages, enhanced retention, and endurance characteristics. The measurements are further confirmed by plotting the energy band diagram of the structures, calculating the quantum tunneling probabilities, and analyzing the charge transport mechanism. Also, the required program time of the memory with ultra-thin asymmetric Al2O3/HfO2 tunnel oxide with graphene nanoplatelets storage layer is calculated under Fowler-Nordheim tunneling regime and found to be 4.1 ns making it the fastest fully programmed MOS memory due to the observed pure electrons storage in the graphene nanoplatelets. With Si nanoparticles, however, the program time is larger due to the mixed charge storage. The results confirm that band-engineering of both tunnel oxide and charge trapping layer is required to enhance the current non-volatile memory characteristics.

[1]  F. Schwierz Graphene transistors. , 2010, Nature nanotechnology.

[2]  A. K. Okyay,et al.  Silicon nanoparticle charge trapping memory cell , 2014 .

[3]  A. K. Okyay,et al.  Enhanced memory effect via quantum confinement in 16 nm InN nanoparticles embedded in ZnO charge trapping layer , 2014 .

[4]  Raphael Tsu,et al.  Simple model for the dielectric constant of nanoscale silicon particle , 1997 .

[5]  D. Kwong,et al.  A novel MONOS-type nonvolatile memory using high-/spl kappa/ dielectrics for improved data retention and programming speed , 2004 .

[6]  D. Kwong,et al.  A novel high-/spl kappa/ SONOS memory using TaN/Al/sub 2/O/sub 3//Ta/sub 2/O/sub 5//HfO/sub 2//Si structure for fast speed and long retention operation , 2006 .

[7]  L. Mitas,et al.  Silicon Nanoparticles. New Photonic and Electronic Material at the Transition Between Solid and Molecule , 2008 .

[9]  Zinc-oxide charge trapping memory cell with ultra-thin chromium-oxide trapping layer , 2013 .

[10]  A. Kis,et al.  Nonvolatile memory cells based on MoS2/graphene heterostructures. , 2013, ACS nano.

[11]  D. R. Strachan,et al.  Surface potentials and layer charge distributions in few-layer graphene films. , 2008, Nano letters.

[12]  E. Fitzgerald,et al.  Conduction band discontinuity and electron confinement at the SixGe1−x/Ge interface , 2010 .

[13]  G. Vidal,et al.  Exact entanglement renormalization for string-net models , 2008, 0806.4583.

[14]  Eicke R. Weber,et al.  Distinction between the Poole-Frenkel and tunneling models of electric-field-stimulated carrier emission from deep levels in semiconductors , 2000 .

[15]  L. Mitas,et al.  Observation of a magic discrete family of ultrabright Si nanoparticles , 2002 .

[16]  D. Chan,et al.  Wide memory window in graphene oxide charge storage nodes , 2010 .

[17]  Roberto Orlando,et al.  First-principles study of the structural, electronic, and optical properties of Ga 2 O 3 in its monoclinic and hexagonal phases , 2006 .

[18]  Osama M. Nayfeh Nonvolatile memory devices with colloidal, 1.0 nm silicon nanoparticles: principles of operation, fabrication, measurements, and analysis , 2009 .

[19]  Andre K. Geim,et al.  Electric Field Effect in Atomically Thin Carbon Films , 2004, Science.

[20]  A. K. Okyay,et al.  Diode behavior in ultra-thin low temperature ALD grown zinc-oxide on silicon , 2013 .

[21]  Sandip Tiwari,et al.  Fast and long retention-time nano-crystal memory , 1996 .

[22]  Jane P. Chang,et al.  Electrical performance of Al2O3 gate dielectric films deposited by atomic layer deposition on 4H-SiC , 2007 .

[23]  E. Villaseñor Introduction to Quantum Mechanics , 2008, Nature.

[24]  M. Ogawa,et al.  Comparisons of Performance Potentials of Si and InAs Nanowire MOSFETs Under Ballistic Transport , 2012, IEEE Transactions on Electron Devices.

[25]  A. Al-Muhanna,et al.  Current-less anodization of intrinsic silicon powder grains: Formation of fluorescent Si nanoparticles , 2007 .

[26]  H. Grubin The physics of semiconductor devices , 1979, IEEE Journal of Quantum Electronics.

[27]  F. Caruso,et al.  Layer-by-layer assembled charge-trap memory devices with adjustable electronic properties. , 2007, Nature nanotechnology.

[28]  Nazek El-Atab,et al.  Transparent Graphene Nanoplatelets for Charge Storage in Memory Devices , 2014 .

[29]  Dim-Lee Kwong,et al.  A novel MONOS-type nonvolatile memory using high-/spl kappa/ dielectrics for improved data retention and programming speed , 2004, IEEE Transactions on Electron Devices.

[30]  S. Alkis,et al.  Low power zinc-oxide based charge trapping memory with embedded silicon nanoparticles via poole-frenkel hole emission , 2014 .

[31]  S. Alkis,et al.  Memory effect by charging of ultra‐small 2‐nm laser‐synthesized solution processable Si‐nanoparticles embedded in Si–Al2O3–SiO2 structure , 2015 .

[32]  Dim-Lee Kwong,et al.  Metal nanocrystal memory with high-/spl kappa/ tunneling barrier for improved data retention , 2005 .

[33]  S. Alkis,et al.  Low Power Zinc-Oxide Based Charge Trapping Memory with Embedded Silicon Nanoparticles , 2014 .

[34]  Kwang S. Kim,et al.  Tuning the graphene work function by electric field effect. , 2009, Nano letters.

[35]  Nazek El-Atab,et al.  Enhanced memory effect with embedded graphene nanoplatelets in ZnO charge trapping layer , 2014 .

[36]  Sungho Kim,et al.  A novel TFT with a laterally engineered bandgap for of 3D logic and flash memory , 2010, 2010 Symposium on VLSI Technology.

[37]  Jane P. Chang,et al.  Dielectric property and thermal stability of HfO2 on silicon , 2002 .

[38]  D. Antoniadis,et al.  Memory effects in metal-oxide-semiconductor capacitors incorporating dispensed highly monodisperse 1 nm silicon nanoparticles , 2007 .

[39]  M. Nayfeh,et al.  Ideal anodization of silicon , 1997 .

[40]  A. Geim,et al.  Two-dimensional gas of massless Dirac fermions in graphene , 2005, Nature.