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Trap Reduction through O 3 Post‐Deposition Treatment of Y 2 O 3 Thin Films Grown by Atomic Layer Deposition on Ge Substrates
Author(s) -
Kim Dong Gun,
Kwon Dae Seon,
Lim Junil,
Seo Haengha,
Kim Tae Kyun,
Lee Woongkyu,
Hwang Cheol Seong
Publication year - 2021
Publication title -
advanced electronic materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.25
H-Index - 56
ISSN - 2199-160X
DOI - 10.1002/aelm.202000819
Subject(s) - materials science , annealing (glass) , equivalent oxide thickness , atomic layer deposition , analytical chemistry (journal) , forming gas , thin film , oxide , current density , leakage (economics) , tin , optoelectronics , transistor , nanotechnology , electrical engineering , voltage , composite material , metallurgy , gate oxide , chemistry , physics , macroeconomics , chromatography , quantum mechanics , economics , engineering
For Ge‐based metal‐oxide‐semiconductor field‐effect transistor application, high‐k Y 2 O 3 thin films are deposited on Ge single‐crystal substrate using atomic layer deposition. The primary drawbacks of a metal‐oxide‐semiconductor capacitor with pristine Y 2 O 3 are large hysteresis and high leakage current. Through forming gas annealing (FGA), the leakage current can be reduced by approximately three orders of magnitude, along with the reduction of interface trap density. However, there is still a large hysteresis in the capacitance–voltage curves. O 3 post‐deposition annealing (OPA) is used to solve the problem. The formation of the YGeO x interfacial layer through OPA and the reduction of the defect level of the Y 2 O 3 thin film effectively decrease the hysteresis, which also decreases the leakage current. Additionally, the hysteresis is 690 mV when only FGA is performed. However, it is further reduced to 260 mV through OPA. Moreover, the remote oxygen scavenging effect using TiN/Pt electrodes prevents an unintentional increase in equivalent oxide thickness (EOT). The 4.7 nm thick Y 2 O 3 film results in an EOT of 1.77 nm and leakage current density of 2.1 × 10 −7 A cm −2 (at flat band voltage—1 V) after the OPA.