Stress Dependence of Paramagnetic Point Defects in Amorphous Silicon Oxide
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- 作者：Andrea Leto ; M. Chiara Munisso ; A. Alan Porporati ; Wenliang Zhu ; Giuseppe Pezzotti
- 刊名：Journal of Physical Chemistry A
- 出版年：2008
- 出版时间：May 1, 2008
- 年：2008
- 卷：112
- 期：17
- 页码：3927 - 3934
- 全文大小：498K
- 年卷期：v.112,no.17(May 1, 2008)
- ISSN：1520-5215
文摘
Room-temperature red cathodoluminescence (CL) emission (R band) arising from the paramagnetic point-defect population present in amorphous silicon oxide (SiOx) has been characterized with respect to its shiftupon applied stress, according to a piezo-spectroscopic (PS) approach. The R band (found at around 630 nm)originates from nonbridging oxygen hole centers (NBOHC; 
ges/entities/tbd1.gif">Si-Oges/entities/bull.gif">) generated in the presence of oxygen-excess sites. It is shown that reliable stress assessments can be obtained in silica glass with a relatively highspatial resolution, provided that appropriate spectroscopic procedures are developed to precisely extract fromthe CL spectrum the shift upon stress of the R band, isolated from other partly overlapping bands. Macroscopicand microscopic PS calibration procedures are shown to lead to consistent results on silica materials withdifferent chemical characteristics and, thus, with different intrinsic defect populations. In addition, quantitativecalibrations of both electron probe size and luminescence emission distribution within the electron probe aregiven. As an application of the PS technique, the magnitude of the residual stress piled up (mainly due to athermal expansion mismatch) at a sharp silica/silicon interface has been characterized by taking into accountthe gradient in defect population developed as a function of distance from the interface. In the Results andDiscussion section, brief comments are offered regarding the possible impact of highly spatially resolvedstress assessments in silica glass upon the development of new materials and advanced electronic devices.