Open AccessEffect of blocking and tunnel oxide layers on the charge trapping properties of MIS capacitors with ALD HfO2/Al2O3 nanolaminated films
Author(s) -
D. Spassov,
A. Paskaleva,
E. Guziewicz,
Wojciech Woźniak,
T Stanchev,
Tzvetan Ivanov,
J. Wojewoda-Budka,
Marta Janusz-Skuza
Publication year - 2021
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/1762/1/012038
Subject(s) - capacitor , materials science , oxide , silicon , trapping , equivalent oxide thickness , insulator (electricity) , layer (electronics) , optoelectronics , electrical engineering , composite material , gate oxide , voltage , transistor , metallurgy , ecology , biology , engineering
Electrical and charge trapping properties of HfO 2 /Al 2 O 3 nanolaminated stacks incorporated in three types of metal-insulator-silicon capacitor structures (without blocking and tunnel oxide layers; with 20 nm Al 2 O 3 as blocking oxide and ∼3 nm Al 2 O 3 or thermal SiO 2 as tunnel layer) were investigated. HfO 2 /Al 2 O 3 stacks exhibit a positive initial oxide charge, and adding of the 3 nm Al 2 O 3 tunnel layer to the capacitor doubles the amount of the positive charge and the density. Using SiO 2 as a tunnel layer resulted in a negative initial oxide charge which is interpreted by the effect of dipole formation at the Al 2 O 3 /SiO 2 interface. Tunnel SiO 2 provides lowest density of the interface states at silicon and leakage currents. The insertion of blocking and tunnel oxide layers to the capacitors significantly widens the memory windows; capacitors with a SiO 2 tunnel oxide demonstrate largest memory windows.