TY - JOUR
T1 - Improved leakage current properties of ZrO2/(Ta/Nb)Ox-Al2O3/ZrO2 nanolaminate insulating stacks for dynamic random access memory capacitors
AU - Onaya, Takashi
AU - Nabatame, Toshihide
AU - Sawada, Tomomi
AU - Kurishima, Kazunori
AU - Sawamoto, Naomi
AU - Ohi, Akihiko
AU - Chikyow, Toyohiro
AU - Ogura, Atsushi
N1 - Funding Information:
This study was supported by the World Premier International Research Center Initiative (WPI) and the Ministry of Education, Culture, Sports, Science and Technology (MEXT), and was partly supported by CREST “Phase Interface Science for Highly Efficient Energy Utilization” ( JPMJCR13C3 ), Japan Science and Technology Agency (JST). The authors thank all staff members of the MANA Foundry, WPI-MANA, and NIMS for their support in fabricating the TiN/ZrO 2 /high-k/ZrO 2 /TiN MIM capacitors.
Publisher Copyright:
© 2018 Elsevier B.V.
PY - 2018/6/1
Y1 - 2018/6/1
N2 - The influence of amorphous high-k interlayers, such as Al2O3, (Ta/Nb)Ox (TN), and (Ta/Nb)Ox-Al2O3 (TNA), on the leakage current (J) and dielectric constant (k) for metal-insulator-metal capacitors with ZrO2/high-k/ZrO2 nanolaminate insulating films and TiN electrodes was investigated. The insulating films were prepared by atomic layer deposition followed by post-deposition annealing at 600 °C. The capacitance equivalent thickness (CET) of the capacitors increased in the order ZrO2/(Ta/Nb)Ox/ZrO2 (ZTNZ) < ZrO2/(Ta/Nb)Ox-Al2O3/ZrO2 (ZTNAZ) < ZrO2/Al2O3/ZrO2 (ZAZ), owing to the k values for Al2O3 (~6), TNA (~9), and TN (~11). The J values at 0.6 V for capacitors with a CET of 1.1 nm increased in the order ZTNAZ < ZAZ ZTNZ. The effect of a high-k interlayer on the J characteristics appeared above a thickness of 0.4 nm in the case of Al2O3 and TNA, while a 0.8-nm-thick TN maintained high J values. Based on these results, there are three important factors as a high-k interlayer to reduce J value, such as a band gap larger than that for TN (4.4 eV), a thickness of ≥0.4 nm, and an amorphous structure. Therefore, to achieve the low J and CET, TNA is a promising candidate material for a high-k interlayer for future dynamic random access memory.
AB - The influence of amorphous high-k interlayers, such as Al2O3, (Ta/Nb)Ox (TN), and (Ta/Nb)Ox-Al2O3 (TNA), on the leakage current (J) and dielectric constant (k) for metal-insulator-metal capacitors with ZrO2/high-k/ZrO2 nanolaminate insulating films and TiN electrodes was investigated. The insulating films were prepared by atomic layer deposition followed by post-deposition annealing at 600 °C. The capacitance equivalent thickness (CET) of the capacitors increased in the order ZrO2/(Ta/Nb)Ox/ZrO2 (ZTNZ) < ZrO2/(Ta/Nb)Ox-Al2O3/ZrO2 (ZTNAZ) < ZrO2/Al2O3/ZrO2 (ZAZ), owing to the k values for Al2O3 (~6), TNA (~9), and TN (~11). The J values at 0.6 V for capacitors with a CET of 1.1 nm increased in the order ZTNAZ < ZAZ ZTNZ. The effect of a high-k interlayer on the J characteristics appeared above a thickness of 0.4 nm in the case of Al2O3 and TNA, while a 0.8-nm-thick TN maintained high J values. Based on these results, there are three important factors as a high-k interlayer to reduce J value, such as a band gap larger than that for TN (4.4 eV), a thickness of ≥0.4 nm, and an amorphous structure. Therefore, to achieve the low J and CET, TNA is a promising candidate material for a high-k interlayer for future dynamic random access memory.
KW - (Ta/Nb)O
KW - AlO
KW - Atomic layer deposition (ALD)
KW - Dynamic random access memory (DRAM)
KW - High-k material
KW - Metal-insulator-metal capacitor
KW - ZrO
UR - http://www.scopus.com/inward/record.url?scp=85045571599&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85045571599&partnerID=8YFLogxK
U2 - 10.1016/j.tsf.2018.02.010
DO - 10.1016/j.tsf.2018.02.010
M3 - Article
AN - SCOPUS:85045571599
VL - 655
SP - 48
EP - 53
JO - Thin Solid Films
JF - Thin Solid Films
SN - 0040-6090
ER -