Etched track morphology in SiO₂irradiated with swift heavy ions

Abstract

We examined pore formation in thermally oxidized silicon wafers (SiO2 / Si) by means of swift heavy ion irradiation followed by chemical etching of latent track zones in SiO2 matrix. The samples were irradiated with 710 MeV Bi up to the fluences of (1-5)·108 and 5·10 10 cm −2 . Afterwards the targets were etched in the dilute solutions of hydrofluoric acid for various durations. Scanning electron microscopy was used to probe the processed samples. From the geometric parameters of the pores the etch rate Vt of the tracks and the etch rate V b of bulk a-SiO2 were estimated. The etching behaviour and morphology of the etched tracks has been found to change markedly with fluence. Mutual influence of tracks at their higher densities was analysed in terms of radiation-induced modifications of material around the ion path. It was shown that the morphology of etched tracks did not change after the annealing at 900• C for 30 min.

A new nanoporous material based on amorphous silicon dioxide

“…For the dose of 5 × 10 10 cm -2 , ≈ 22 nm. As was shown earlier [6], according to the data of etching after irradiation with Bi (710 MeV) ions, track core diameter D 0 is 20 nm. Thus, for a bismuth dose of 5 × 10 10 cm -2 , ≈ D 0 .…”

“…They were close to the values reported in [2,3] for tracks in SiO 2 etched in 1% HF. We showed earlier [6] that, with all irradiation and chemical treatment conditions being equal, the diam eter of etched tracks increases linearly with the time of etching in HF solution. This, along with knowledge of V t and V b , allows us to predict the regimes of chemical treatment in HF solutions for making porous SiO 2 lay ers of required thickness with through channels of a given diameter.…”

“…This approach is used to make track mem branes that are used as fine purification filters in organic synthesis, biotechnologies, and medicine from poly meric films. The etching of latent tracks can also be used for making channels in SiO 2 layers on silicon [1][2][3][4][5][6]. Track etching is a threshold process.…”

Tunable nanoporous silicon oxide templates by swift heavy ion tracks technology

“…When immersing irradiated samples into an etching solution, such damaged areas will be etched at a much faster rate than undamaged SiO 2 . This provides the possibility of transforming selectively the latent SHI tracks into pores within the a-SiO 2 layer, by means of controlled chemical etching [53,54,[66][67][68][69]. The higher etching rate of the SHI tracks as compared to the undamaged material is explained by the fact that three-and four-component rings consisting of SiO 4 -tetrahedra emerge along the latent SHI track in a-SiO 2 , instead of energetically favorable six-component rings [70,71].…”

CdTe Nanocrystal Synthesis in SiO2/Si Ion‐Track Template: The Study of Electronic and Structural Properties

“…The conical shape of the pores was due to the comparability in the magnitude rates of the etching of the material in the region of the track Vt and in the volume of the intact matrix Vb. [ 11 ] The conical shape was confirmed by transmission electron microscope studies [ 12,13 ] and atomic‐force microscope. [ 14 ]…”