Semiconductor Physics, Quantum Electronics & Optoelectronics. 2008. V. 11, N 4. P. 311-318.
Microwave induced structural-impurity ordering of transition region
in Ta2O5 stacks on Si
1V. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine
41 Nauky Prospect, 03028 Kyiv, Ukraine
Phone: +(380-44) 525-61-82; e-mail: konakova@isp.kiev.ua
Abstract. The effect of short-term microwave treatment (MT) on the electronic
properties of interface in the Ta 2 O 5 −SiO x −p-Si structures has been investigated. The
samples of two types were studied: check ones (batch I) and those exposed to previous
MT (batch II). The samples were aged (hold in air) at a temperature of ~300 K for two
years. After that, they were exposed to MT during 2, 4, 6 and 8 s. Both before and after
two-year aging and further MT, we measured, for all samples, the spectra of surface-
barrier electroreflectance (SBER) and concentration depth profiles of the components in
the structure, as well as the radii of curvature of heterosystem from which the intrinsic
stress (IS) values were calculated. It was found that the transition energy E g grows with
time of MT for both type samples. This corresponds to decrease of compressing ISs in
27 % in the check sample (with more number of defect) and by 11 % in that previously
exposed to MT. This fact indicates structural-impurity ordering of the Si−SiO x interface.
The surface quantum-dimensional effect occurred after MT. After two-year aging, energy
quantization was observed in the previously irradiated sample for 6 s and in the check
sample (with more number of defects) after MT for 8 s. The most probable mechanism of
improvement of the near-surface properties of SiO x −Si interface is discussed.
Keywords: microwave treatment, Ta2O5−p-Si heterostructure, interface, surface-barrier
electroreflectance, intrinsic stresses, quantum-dimensional effect, structural-impurity
ordering.
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