Soft X‐ray emission spectroscopy of low‐dimensional SiO₂/Si interfaces after Si⁺ ion implantation and ion beam mixing

Abstract

An X-ray Si L 2,3 -emission spectroscopy study of a SiO 2 /n-Si heterostructure containing a thin oxide layer of d ¼ 20 nm thickness implanted by Si þ ions with an energy 12 keV is reported. The maximum concentration of implanted Si þ ions is located close to the SiO 2 -Si interface at a depth of 18 nm leading to an ion-beam mixed SiO 2 /Si interface layer in this region, consisting of a non-stoichiometric SiO x matrix. The possible mechanisms of these processes are discussed by atomic collision cascades (knocking-off and knocking-on processes) during ion implantation, associated by partial phase separation into silicon precipitates and SiO 2 .

Si+ ion implantation in silica and ion beam mixing in SiO2/Si interfaces

“…As for XES Si L 2,3 of the references cSiO 2 and amorphous a-SiO 2 the main D-and E-maxima in both spectra are of Si 3s-and Si 3d origin, respectively, whereas the broad low intensity F-band arises from the hy- for untreated SiO 2 /Si with a sum of the XES Si L 2,3 spectra of the references c-Si and a-SiO 2 spectra taken with corresponding weighting factors of 0.56(c-Si) + 0.44(a-SiO 2 ) , see Ref. [13].…”

“…Moreover, after high fluence Si + ion implantation into and around the interface of the thin 20 nm a-SiO 2 layer on c-Si the formation of an ion-beam mixed buffer layer SiO x in this region was detected by means of soft Xray emission spectroscopy (SXES), see Fig. 4, and compared with a TRIDYN computer simulation of ion implantation and ion beam mixing [13]. This structure modulation is due to atomic knock-on and knock-off effects and respective ion beam mixing processes during the highfluence Si + ion implantation into the interface region, see Fig.…”

“…The rest is still dispersed in the SiO 2 matrix, better said SiO x matrix. We may describe this incomplete phase separation [12,13] by the rate equation:…”

“…The X-ray Si L 2,3 -emission spectra from Si 3d3s → Si 2p 1/2,3/2 valence transitions were recorded with a SPECTROZOND ultrasoft X-ray spectrometer with high spatial (4 μm) and energy (ΔЕ = 0.3 eV) resolution [13]. Spectra were measured with electron beam acceleration voltages U = 2, 4, and 6 kV.…”

Формирование нанокристаллов кремния в многослойных нанопериодических структурах a-SiO-=SUB=-x-=/SUB=-/диэлектрик по результатам синхротронных исследований

“…Для исследования изменений, про-исходящих при формировании и высокотемпературных отжигах (ВТО) подобных МНС, важно применение неразрушающих методов диагностики, чувствительных к составу и структуре поверхности, границам раздела, ло-кальному атомному окружению. К таковым традиционно относятся методы рентгеновской спектроскопии [8,9], в частности метод спектроскопии ближней тонкой струк-туры края рентгеновского поглощения (XANES -X-ray absorption near edge structure) с использованием синхротронного излучения [10][11][12]. Ранее исследования поверхностных слоев (∼ 5 нм) для МНС a-SiO x /Al 2 O 3 показали образование ncl-Si [7,12] в результате ВТО.…”