TiO[sub 2]∕Al[sub 2]O[sub 3]∕TiO[sub 2] Nanolaminated Thin Films for DRAM Capacitor Deposited by Plasma-Enhanced Atomic Layer Deposition

Ti O 2 ∕ Al 2 O 3 ∕ Ti O 2 nanolaminated thin films investigated for the application of dynamic random access memory (DRAM) capacitor dielectrics. Ti O 2 is a promising high- k material, but its leakage current property is poor. Al 2 O 3 nanolaminated film was inserted between two amorphous Ti O 2 layers, and an Al 2 O 3 thickness greater than 10 Å effectively reduced the leakage current. When Ti O 2 layers were crystallized to enhance the dielectric constant, a thicker Al 2 O 3 sublayer was required. As a result, anatase- Ti O 2 ( 40 Å ) ∕ Al 2 O 3 ( 12.5 Å ) /rutile- Ti O 2 ( 40 Å ) nanolaminated film is suggested as an optimal structure that gives k = 44 (equivalent oxide thickness) with a leakage current of 6.46 × 10 − 7 A ∕ cm 2 at 1 MV ∕ cm .