Atomic layer deposition of high capacitance density Ta2O5-ZrO2 based dielectrics for metal-insulator-metal structures

We have investigated electrical properties of laminated atomic layer deposited films: ZrO"2-Ta"2O"5, ZrO"2-Nb"2O"5-Ta"2O"5, ZrO"2-Ta"xNb"1"-"xO"5 and Ta"2O"5-Zr"xNb"yO"z. Even though the capacitances of laminates were often higher compared to films of constituent materials with similar thickness, considerably higher charge storage factors, Q, were achieved only when tetragonal ZrO"2 was stabilized in ZrO"2-Ta"2O"5 laminate and when the laminate thickness exceeded 50nm. The decreased Q values in the case of most laminates were the result of increased leakage currents. In the case of thinner films only Ta"2O"5-Zr"xNb"yO"z stack possessed capacitance density and Q value higher than reference HfO"2. Concerning the conduction mechanisms, in the case of thinner films, the Ta"2O"5 or Ta"xNb"1"-"xO"5 apparently controlled the leakage either by Richardson-Schottky emission or Poole-Frenkel effect.

[1]  Byung Jin Cho,et al.  Physical and electrical characterization of HfO2 metal-insulator-metal capacitors for si analog circuit applications , 2003 .

[2]  M. Chonko,et al.  Effect of silicon substrate microroughness on gate oxide quality , 1996 .

[3]  Ho Jin Cho,et al.  New TIT Capacitor with ZrO2/Al2O3/ZrO2 dielectrics for 60nm and below DRAMs , 2006, 2006 European Solid-State Device Research Conference.

[4]  Krishna C. Saraswat,et al.  Atomic layer deposition of ZrO2 on W for metal-insulator-metal capacitor application , 2003 .

[5]  Sang-Won Kang,et al.  Enhancement of dielectric constant in HfO2 thin films by the addition of Al2O3 , 2006 .

[6]  H. Chung,et al.  TiO2 ∕ Al2O3 ∕ TiO2 Nanolaminated Thin Films for DRAM Capacitor Deposited by Plasma-Enhanced Atomic Layer Deposition , 2008 .

[7]  H. Hwang,et al.  Thermal Leakage Improvement by Using a High-Work-Function Ni Electrode in High- κ TiHfO Metal–Insulator–Metal Capacitors , 2007 .

[8]  Simon M. Sze,et al.  Current Transport and Maximum Dielectric Strength of Silicon Nitride Films , 1967 .

[9]  Charge trapping effect at the contact between a high-work-function metal and Ta2O5 high-k dielectric , 2008 .

[10]  Chun-Yen Chang,et al.  High-density MIM capacitors with HfO2 dielectrics , 2004 .

[11]  K. Kukli,et al.  PROPERTIES OF ATOMIC LAYER DEPOSITED (TA1-XNBX)2O5 SOLID SOLUTION FILMS AND TA2O5-NB2O5 NANOLAMINATES , 1999 .

[12]  David Vanderbilt,et al.  Phonons and lattice dielectric properties of zirconia , 2001, cond-mat/0108491.

[13]  J. Simmons.  Conduction in thin dielectric films , 1971 .

[14]  K. Kukli,et al.  Properties of (Nb1 − xTax)2O5 solid solutions and (Nb1 − xTax)2O5-ZrO2 nanolaminates grown by Atomic Layer Epitaxy , 1997 .

[15]  T. Pan,et al.  Good High-Temperature Stability of $\hbox{TiN}/ \hbox{Al}_{2}\hbox{O}_{3}/\hbox{WN}/\hbox{TiN}$ Capacitors , 2007, IEEE Electron Device Letters.

[16]  Ran Liu,et al.  High-temperature conduction behaviors of HfO2/TaN-based metal-insulator-metal capacitors , 2007 .

[17]  J. Autran,et al.  Comparison between the properties of amorphous and crystalline Ta2O5 thin films deposited on Si , 1999 .

[18]  B. E. White,et al.  Impact of Zr addition on properties of atomic layer deposited HfO2 , 2006 .

[19]  M. Kaiser,et al.  Spontaneous nanoclustering of ZrO2 in atomic layer deposited LayZr1−yOx thin films , 2008 .

[20]  J. Simmons,et al.  ac electrical properties and I‐V characteristics of MoO3 film under dc bias , 1972 .

[21]  Pascale Mazoyer,et al.  Evolution of materials technology for stacked-capacitors in 65 nm embedded-DRAM , 2005 .

[22]  S. Blonkowski,et al.  Investigation and modeling of the electrical properties of metal–oxide–metal structures formed from chemical vapor deposited Ta2O5 films , 2001 .

[23]  Mikko Ritala,et al.  Tailoring the dielectric properties of HfO2–Ta2O5 nanolaminates , 1996 .

[24]  C. Hwang,et al.  Impact of O3 feeding time on TiO2 films grown by atomic layer deposition for memory capacitor applications , 2007 .

[25]  Mikko Ritala,et al.  Atomic layer deposition of Al2O3, ZrO2, Ta2O5, and Nb2O5 based nanolayered dielectrics , 2002 .

[26]  P. Joshi,et al.  The Enhanced Dielectric and Insulating Properties of Al2O3 Modified Ta2O5 Thin Films , 2003 .

[27]  K. Kukli,et al.  Niobium Oxide Thin Films Grown by Atomic Layer Epitaxy , 1998 .

[28]  Mikko Ritala,et al.  Atomic layer epitaxy growth of tantalum oxide thin films from Ta(OC{sub 2}H{sub 5}){sub 5} and H{sub 2}O , 1995 .

[29]  H. Roetschi,et al.  A.C. polarisation in B-modification Nb2O5 single crystals , 1968 .

[30]  K.C. Chiang,et al.  Very high-density (23 fF//spl mu/m/sup 2/) RF MIM capacitors using high-/spl kappa/ TaTiO as the dielectric , 2005, IEEE Electron Device Letters.

[31]  Marianna Kemell,et al.  Exploitation of atomic layer deposition for nanostructured materials , 2007 .

[32]  Yung-Hsien Wu,et al.  High density metal-insulator-metal capacitor based on ZrO2∕Al2O3∕ZrO2 laminate dielectric , 2008 .

[33]  M. Gros-Jean,et al.  In situ electric field simulation in metal/insulator/metal capacitors , 2006 .

[34]  K. Kukli,et al.  Properties of Ta2 O 5‐Based Dielectric Nanolaminates Deposited by Atomic Layer Epitaxy , 1997 .