Title :
A heteroepitaxial MIM-Ta/sub 2/O/sub 5/ capacitor with enhanced dielectric constant for DRAMs of G-bit generation and beyond
Author :
Hiratani, M. ; Hamada, Takahiro ; Iijima, S. ; Ohji, Y. ; Asano, I. ; Nakanishi, N. ; Kimura, S.
Abstract :
We demonstrate a novel MIM capacitor with a heteroepitaxial Ta/sub 2/O/sub 5/ dielectric, the permittivity of which is as high as 50. The heteroepitaxy of Ta/sub 2/O/sub 5/ on the Ru electrode changes its crystal symmetry from a conventional orthorhombic system to a hexagonal one. One-dimensional Ta-O-Ta chains along the c-axis bring about delocalized electrons, large polarizability and thus enhanced permittivity. This technology is promising for the application of Ta/sub 2/O/sub 5/ to Gbit DRAMs, eliminating the need to use such exotic materials as BST and STO.
Keywords :
DRAM chips; MIM devices; MOCVD; crystal symmetry; permittivity; polarisability; tantalum compounds; thin film capacitors; vapour phase epitaxial growth; 1D Ta-O-Ta chains; BST; DRAMs; MIM capacitor; Ru electrode; STO; Ta/sub 2/O/sub 5/ heteroepitaxy; Ta/sub 2/O/sub 5/-Ru; crystal symmetry; delocalized electrons; dielectric constant; heteroepitaxial MIM-Ta/sub 2/O/sub 5/ capacitor; heteroepitaxial Ta/sub 2/O/sub 5/ dielectric; hexagonal system; orthorhombic system; permittivity; polarizability; Capacitors; Crystallization; Dielectric constant; Dielectric substrates; Electrodes; High K dielectric materials; High-K gate dielectrics; Lattices; Permittivity; Random access memory;
Conference_Titel :
VLSI Technology, 2001. Digest of Technical Papers. 2001 Symposium on
Conference_Location :
Kyoto, Japan
Print_ISBN :
4-89114-012-7
DOI :
10.1109/VLSIT.2001.934937
