Paramagnetic defect centers in BESOI and SIMOX buried oxides

Abstract

We have combined electron paramagnetic resonance and capacitance-voltage measurements to identify the chemical nature and charge state of defects in BESOI and SIMOX materials. The four types of defect centers observed, charged oxygen vacancies, delocalized hole centers, amorphous-Si centers, and oxygen-related donors, are strikingly similar. In the BESOI materials, the radiation-induced EPR centers are located at or near the bonded interface. Therefore, the bonded interface is a potential hole trap site and may lead to radiation-induced back-channel leakage. In SIMOX materials it is found that all of the defects in the buried oxide are due to excess-Si. Our results using poly-Si/thermal oxide/Si structures strongly suggest that it is the post-implantation, high temperature anneal processing step in SIMOX that leads to their existence. The anneal leads to the outdiffusion of oxygen from the buried oxide creating excess-Si related defects in the oxide and O-related donors in the underlying Si substrates. Last, our study has elucidated a number of interesting aspects regarding the physical nature of a relatively new class of defects in Si02: delocalized spin centers. We find that they are hole traps in both SIMOX and BESOI materials.

Observation and electronic characterization of two E′ center charge traps in conventionally processed thermal SiO2 on Si

“…The new EЈ variant observations include a ''peculiar'' line shape in separation by implanted oxygen ͑SIMOX͒ buried oxides, 9,10 the 10.4 G doublet 11,12 and 74 G doublet 11,13,14 hydrogen complexed EЈ center spectra, the ''EX'' center 15 in home grown thermal SiO 2 , the ''EH'' center 16 in bond and etchback ͑BESOI͒ buried oxides, and E ␦ Ј-like centers. 5, [17][18][19] The ''EX'', ''EH'', E ␦ Ј, and ''peculiar line shape'' observations all involve a sharp line shape with a zero crossing gХ2.002, similar to a line shape observed in bulk fused silica by Griscom and Friebele. 20 In this letter, we compare electronic properties of two EЈ variants which can be generated in a variety of thermally grown thin oxide films.…”

“…4 -8 For quite some time, no explicit distinction was made with regard to possible variations in EЈ line shapes or structures in thin SiO 2 films. Recently though, a menagerie of ''new'' EЈ variants [9][10][11][12][13][14][15][16][17][18][19] has been reported, almost entirely in exotic SiO 2 thin films. The new EЈ variant observations include a ''peculiar'' line shape in separation by implanted oxygen ͑SIMOX͒ buried oxides, 9,10 the 10.4 G doublet 11,12 and 74 G doublet 11,13,14 hydrogen complexed EЈ center spectra, the ''EX'' center 15 in home grown thermal SiO 2 , the ''EH'' center 16 in bond and etchback ͑BESOI͒ buried oxides, and E ␦ Ј-like centers.…”

Influence of total-dose radiation on the electrical characteristics of SOI MOSFETs

“…The SOI substrate technology most extensively studied is SIMOX technology. In SI-MOX material, nearly all of the defects in the buried oxide are due to excess silicon, indicating that the post-implantation, high temperature anneal step used to form the buried oxide is the source of the defects [18]. The primary defect identified by EPR is the E 0 c center [19][20][21][22][23][24][25], similar to that for gate oxides.…”

“…One of these is a relatively new class of defect center, the E 0 d defect [24][25][26][27]. The E 0 d defect is a metastable hole trap with a high capture cross-section that anneals at a much lower temperature than the E 0 c defect [14,18]. Hence, in space or other low-dose-rate environments, it is not expected that E 0 d defects would play a significant role in BOX charge trapping.…”

Low Dose Rate Effects in Silicon Based Devices and Integrated Circuits: A Review

“…Однако в случае толстых захороненных оксидов в КНИ−структурах и полевых оксидов, а также в ряде случаев подза-творных оксидов такая корреляция может отсут-ствовать [10][11][12][13][14][15]. Это по−прежнему определяет ак-туальность задачи исследования природы дефектов, отвечающих за накопление положительного заряда в оксидах.…”