Thermal Oxidation Rate of a Si<sub>3</sub>N<sub>4</sub>Film and Its Masking Effect against Oxidation of Silicon

Solid-state nanopores are considered a promising tool for the study of biological polymers such as DNA and RNA, due largely to their flexibility in size, potential in device integration and robustness. Here, we show that the precise shape of small nanopores (∼5 nm diameter in 20 nm SiN membranes) can be controlled by using transmission electron microscope (TEM) beams of different sizes. However, when some of these small nanopores are immersed in an aqueous solution, their resistance is observed to decrease over time. By comparing nanopores of different shapes using (scanning) TEM both before and after immersion in aqueous solution, we demonstrate that the stability of small nanopores is related to their three-dimensional geometry, which depends on the TEM beam size employed during pore fabrication. Optimal stability is obtained using a TEM beam size of approximately the same size as the intended nanopore diameter. In addition, we show that thermal oxidation can serve as a means to independently control nanopore size following TEM fabrication. These observations provide key guidelines for the fabrication of stable solid-state nanopores on the scale of nucleic acids and small proteins.

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“…Comparison of our observed growth rate with reported values [20] is not possible as these were measured under very different conditions (900-1100…”

Section: Resultsmentioning

confidence: 79%

“…• C for such thin films as employed in our experiments [20]. This slow rate is useful, as it allows for very fine control over the thickness.…”

Section: Resultsmentioning

confidence: 99%

Controlling nanopore size, shape and stability

et al. 2010

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“…However, the absolute times are too small to allow detailed conclusions, Effective nitride thicknesses.~The oxidation resistance can be converted into an effective thickness of a silicon nitride layer at the Si/SiO2 interface. For this purpose the following assumptions have to be made: (i) The interfacial nitride-like layer can be considered to be a true Si3N4 layer and hence to show the same oxidation kinetics as SigN4, as described by Enomoto (12); (ii)., the presence of the initial oxide can be considered to be the result of the conversion of an equivalent thickness of Si3N4 that has taken place in the past; and (iii) the oxidation kinetics of Si3N4 are equally valid for layers thinner than 5 nm as for thicker layers. The oxidation mechanism of silicon nitride has been described by Enomoto et at.…”

Section: 2mentioning

confidence: 99%

“…The oxidation mechanism of silicon nitride has been described by Enomoto et at. (12). The oxidation characteristic of silicon nitride covered with an initial oxide layer of thickness x0 is given by…”

Section: 2mentioning

confidence: 99%

The Oxidation Inhibition in Nitrogen‐Implanted Silicon

Josquin

Tamminga

1982

J. Electrochem. Soc.

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In order to reveal the mechanism of oxidation inhibition in nitrogen-implanted silicon, the ~SN(p, ~y)'~C resonant nuclear reaction has been applied to obtain detailed information on nitrogen concentration profiles in silicon. It appears that the oxidation resistance is caused by an extremely thin (<3 nm) nitrogen-rich layer at the Si-SiO2 interface. The formation of this interfacial nitride-like layer is the result of complicated redistributions of the nitrogen which take place during annealing and oxidation. It is shown that implantation of nitrogen ions into source and drain areas of an MOS transistor can be used to inhibit further growth of the gate oxide in these areas during a subsequent oxidation and thus allows a selective oxidation of polysilicon gates. This provides a novel technique for obtaining self-aligned contact windows to the source and drain regions. Finally reverse current measurements on gate-controlled diodes show that the bulk and surface generation currents in the nitrogen-implanted layer are as low as for unimplanted reference wafers, provided adequate experimental conditions are applied.The retardation of the thermal oxidation of silicon has attracted a growing interest in recent years (1-4). Most results concern the thermal nitridation of silicon: silicon wafers covered with thin SiO2 layers are treated in nitrogen or ammonia atmospheres at high temperatures to obtain an oxidation resistance that is due to the formation of an interfacial oxynitride layer (1). On the other hand, several authors have reported that nitrogen ion implantation can also be used to retard the oxidation of silicon (5-8). Most of these studies have concentrated on high dose implantations as an alternative to the conventional LOCOS process. Although the effects of lower nitrogen doses upon the thermal oxidation of silicon were mentioned as early as 1973 (5), no attempts to apply these results in semiconductor device technology have yet been published.The lack of detailed knowledge on nitrogen profiles in silicon has been the main obstacle to elucidating the mechanism of oxidation inhibition in nitrogen implanted silicon and to finding the optimum conditions for its application in device technology.In the present study the 15N(p, aT)~2C resonant nuclear reaction is used for the depth profiling of nitrogen to obtain detailed information on the redistribution of nitrogen profiles in silicon. These redistributions provide a satisfactory explanation of the observed oxidation resistance for a variety of implantation parameters and oxidation conditions. In many cases even a first-order quantitative model can be applied. Furthermore, as it was found ~hat moderate doses of nitrogen ions can be sufficient to induce useful oxidation resistances, the nitrogen ion implantation is shown to provide an excellent way to obtain selfaligned contact windows to source and drain areas in MOS technology. Finally the effect of nitrogen ion implantation upon bulk and surface generation currents in gate-controlled diodes is discussed. Exper...

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“…In this step, the frontside SiRN layer protects the polysilicon layer from oxidation. In the etch ports, the 30 nm Si 3 N 4 plays the same role [5]. Having the thin oxide layer at the etch ports' sidewalls provides a good connection point for the grown oxide.…”

Section: Fabricationmentioning

confidence: 99%

Fabrication of dense flow sensor arrays on flexible membranes

Izadi

Boer

Berenschot

et al. 2009

TRANSDUCERS 2009 - 2009 International Solid-State Sensors, Actuators and Microsystems Conference

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Biological sensory systems often display great performance which inspires engineers to design artificial counterparts. In this paper we report the fabrication of aquatic hair based flow sensors inspired by fish lateral line. Geometrically optimized flexible membranes of SU-8 with integrated electrodes underneath have been realized in a reliable, high yield process. By separating the liquid medium from readout electrodes we decrease squeeze film damping and eliminate electrolysis. The procedure allows dense membrane array fabrication.

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Thermal Oxidation Rate of a Si₃N₄Film and Its Masking Effect against Oxidation of Silicon

Cited by 54 publications

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Controlling nanopore size, shape and stability

Controlling nanopore size, shape and stability

The Oxidation Inhibition in Nitrogen‐Implanted Silicon

Fabrication of dense flow sensor arrays on flexible membranes

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Thermal Oxidation Rate of a Si3N4Film and Its Masking Effect against Oxidation of Silicon

Cited by 54 publications

References 0 publications

Controlling nanopore size, shape and stability

Controlling nanopore size, shape and stability

The Oxidation Inhibition in Nitrogen‐Implanted Silicon

Fabrication of dense flow sensor arrays on flexible membranes

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Product

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Thermal Oxidation Rate of a Si₃N₄Film and Its Masking Effect against Oxidation of Silicon