We are proposing a novel fabrication method for single crystal diamond scanning probes for atomic force microscopy (AFM), exploiting Faraday cage angled etching (FCAE). Common, oxygen-based, inductively coupled plasma (ICP) dry etching processes for diamond are limited with respect to the achievable geometries. The fabrication of freestanding micro- and nanostructures is therefore challenging. This is a major disadvantage for several application fields e.g., for realizing scanning magnetometry probes based on nitrogen vacancy (NV) centres and capable of measuring magnetic fields at the nanoscale. Combining a planar design with FCAE and state-of-the-art electron beam lithography (EBL) yields a reduction of process complexity and cost compared to the established fabrication technology of micro-opto-mechanical diamond devices. Here, we report on the direct comparison of both approaches and present first proof-of-concept planar-FCAE-prototypes for scanning probe applications.

A CoNiCrAlTaHfY/Co composite coating was prepared on the etched C/C composites by using duplex vapor phase surface alloying treatments, i.e., Co alloying and Co–Ni–Cr–Al–Ta–Hf–Y alloying. Microstructures and oxidation behavior of the coated C/C composites were analyzed by scanning electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction. The result showed that the CoNiCrAlTaHfY/Co composite coating, 25 μm in thickness, was compact and composed of CrCoTa, AlCo2Ta, AlxCry, AlxNiy, and Co. The coating adhesion can be enhanced by microwave plasma chemical vapor deposition etching of matrix surface and adding a Co intermediate layer between the CoNiCrAlTaHfY top layer and C/C composites substrate. The honeycomb structure after etching was helpful to alloying element absorb and diffuse into substrate surface, and the composite coating continuation was improved by the Co buffer layer. After exposing in air for 180 min at 1000 °C, the bulk C/C composites volatilized while the loss rate of coated C/C composites was 0.82%, showing an improved oxidation resistance. Mixed oxides mainly containing Al2O3 and Cr2O3 were formed in the composite coating surface and protected the C/C composites from oxidation in air.

The synergetic effects of surface smoothing exhibited during the inductively coupled plasma reactive ion etching (ICP-RIE) of free-standing polycrystalline diamonds (PCDs) were investigated. Changing the assistive gas types generated variable surface oxidation states and chemical environments that resulted in different etching rates and surface morphologies. The main reaction bond mechanism (C–O) during ICP-RIE and the ratio of C–O–C/O–C=O associated with the existence of a uniform smooth surface with root mean square (RMS) roughness of 2.36 nm were observed. An optimal process for PCD smoothing at high etching rate (4.6 μm/min) was achieved as follows: 10% gas additions of CHF3 in O2 plasma at radio frequency power of 400 W. The further etched ultra-smooth surface with RMS roughness <0.5 nm at etching rate of 0.23 μm/min that being produced by transferring this optimum recipe on single crystal diamonds with surface patterns confirmed the effectiveness of the fast smoothing approach and its feasibility for diamond surface patterning.

AlN etching with chloride plasmas is studied. The experimental results show that the etching of AlN under a low pressure Cl2/Ar plasma mixture in moderate DC bias is not possible. The addition of BCl3 gas to Cl2/Ar mixture allows the etching of AlN materials. However the obtained properties of etched AlN is still not in conformity with the technological specification especially for the condition which the etched AlN must be kept only along the sidewall of the InP laser cavity and be removed elsewhere (selective etching). To know more about the effect of the BCl3 addition to the Cl2/Ar plasma mixture, global model of BCl3/Cl2/Ar is developed to quantify the neutral and ion densities as well as the electron density and temperature. The simulation results show that the electron density and low pressure linearly varies with the RF power. The negative ion density decreases with the percentage of BCl3 leading to the diminution of the electronegativity which is represented by negative ion to electron density ratio. The simulation shows that the positive ion to atomic chlorine flux ratio increases with the %BCl3. Such parameters could play an important role in the ion neutral synergy during the etching process.

The effect of damage induced by plasma etching on the cathodoluminescence intensity of micron-size InP features is studied. At the etched bottom, it is found that the hard mask stripping process is sufficient to recover the luminescence. Within features, the presence of sidewalls reduces luminescence intensity due to additional non-radiative surface recombinations. For a n-doped sample, a carrier diffusion length of 0.84 μm and a reduced nonradiative surface recombination velocity of 2.58 are calculated. Hydrostatic strain within the etched features is measured using the peak shift of the luminescence signal, while in plane strain anisotropy is obtained from its degree of polarization, both with a resolution of about 100 nm.

We demonstrate anisotropic, vertical deep etching of graphite and densely packed carbon nanotube (CNT) thick layer beyond the micrometer scale, which representing the first step toward nanocarbon bulk micromachining. This micromachining process is compatible with standard lithography and therefore allows the fabrication of graphite and CNT architectures with 1 μm lateral resolution and up to 10 μm scale depth.

We investigated the fabrication of diamond-like carbon (DLC) emitter patterns by room-temperature curing nanoimprint lithography (RTC-NIL) with polydimethylsiloxane (PDMS) molds using polysiloxane, as an application to the emitter for the next generation flat panel display.

The DLC which has excellent properties similar to diamond properties was used as a pattern material. A PDMS was used as a mold material and fabricated by the following optimum conditions of the first curing time at RT for 36 h and the second curing time at the temperature of 150 °C for 15 mins. The polysiloxane is in the state of sticky liquid at RT and stable in air. Therefore, the polysiloxane was used the electron beam (EB) resist and oxide mask material in EB lithography, and also used as RT-imprint material.

First, we fabricated the PDMS mold with pit array. Each dot is 5 µm-diameter and 400 nm-depth. We carried out the RTC-NIL process with PDMS molds using polysiloxane under the following optimum imprint conditions of 0.5 MPa-imprinting pressure, 1.5 min-the time between spin-coat and imprint, and 5 min-imprinting time. Next, the residual layer of imprinted polysiloxane pattern was 450 nm and then was removed with electron cyclotron resonance (ECR) trifluoromethane (CHF3) ion shower under the conditions of 300 eV-ion energy and 3 min-etching time. Then, we processed the imprinted polysiloxane patterns on the DLC film with an ECR oxygen (O2) ion shower under the conditions of 400 eV-ion energy and 12 min-etching time. As a result, we succeeded in fabricating convex DLC emitter patterns with high accuracy which has 5 µm-diameter and 500 nm-height.

We present here a reactive ion etching recipe to fabricate germanium nanowires. We used a combination of Cl2, N2 and O2 and studied the influence of both the gas pressure and the O2 mass flow on the morphology of the nanowires. 5 µm long nanowires with an aspect ratio of 20 are demonstrated with smooth surfaces and a tapering below 20 nm/µm. We also show that both gold and aluminum can be used as hard mask; the latter achieving a selectivity with germanium above 100.

We investigated the fabrication of convex diamond-like carbon (DLC) based microgears in room-temperature curing nanoimprint lithography (RTC-NIL) using the ladder-type hydrogen silsesquioxane (HSQ), as an application for the medical micro electro mechanical system (MEMS). The HSQ which is an inorganic polymer of sol-gel system turns into a gel when exposed to air and has the siloxane bond. Therefore, the HSQ was used as RT-imprinting material, and also used as an oxide mask material in electron cyclotron resonance (ECR) oxygen (O2) ion shower etching. We fabricated the polydimethylsiloxane (PDMS) mold with concave microgear patterns which has 40, 50 and 60 μm-tip diameter and 300 nm-depth. We carried out the RTC-NIL process using the PDMS mold under the following optimum conditions of 0.10 MPa-imprinting pressure and 1.0 min-imprinting time. We found that the residual layer of imprinted HSQ microgear patterns was removed with ECR trifluoromethane (CHF3) ion shower under the following conditions of 300 eV-ion energy and 2.0 min-etching time, and then microgears of the HSQ on the DLC film were etched with ECR O2 ion shower under the following conditions of 400 eV-ion energy and 10 min-etching time. As a result, the convex DLC based microgears which have 40, 50 and 60 μm-tip diameter and 400 nm-height were fabricated with high accuracy in the new fabrication process of RTC-NIL.

To overcome various concerns due to scaling-down device size in future large-scale integration (LSI), it is indispensable to introduce a new concept of heterogeneous three-dimensional (3D) integration in which various kinds of device chips with different sizes, devices, and materials are vertically stacked. To achieve such heterogeneous 3D integration, the key technology of self-assembly and electrostatic (SAE) bonding has been developed. The heterogeneous 3D integration technology with the SAE bonding method has enabled 3D heterogeneous stacking of different types of chips such as the compound semiconductor device chip, photonic device chip, and spintronic device chip on complementary metal oxide semiconductor chips. A 3D image sensor with extremely fast processing speed and a 3D microprocessor with a self-test and self-repair function for future automatic driving vehicles are typical examples of heterogeneous 3D LSIs which we fabricated by the SAE bonding method.

We present a methodology to enhance the electrical capacitance of activated carbon (AC) electrodes based on the introduction of electrically charged defects through argon plasma processing. Extensive characterization using electrochemical techniques incorporating cyclic voltammetry, constant current charge/discharge, and electrical impedance spectroscopy indicated a close to seven-fold increase in capacitance with respect to untreated AC electrodes, not subject to plasma processing.

The purpose of the present paper is to investigate the composition of the coating formed on the plasma reactor walls after an industrial process which is divided into two steps, where the chemistries used are CF4/CH2F2 followed by HBr/O2. Since Fluorine traces have been detected through the plasma and over the wafer even during the second chemistry, investigations of the Br-F chemistry duality for a new silicon etching process have been performed in order to see the reactions which are taking place inside of the reactor. The understanding of these formations is really important to avoid process instabilities and get better performance of the transistors. The coating on the walls after the process and after the cleaning between wafers has been characterized in order to figure out the level of F traces after each step and to understand the reminiscence of this element over time. This study is the starting point to propose a modification on the Waferless AutoClean (WAC) used nowadays in an industrial process.

To improve the integrated circuits’ performance and continue the downscaling of dimensions, it is necessary to use low dielectric constant materials as interconnects insulators. Current porous SiCOH low-k dielectrics are now reaching their limits since their porosity enables the diffusion of species that modify the inner surface of the pores. To further reduce the dielectric constant, it is necessary to change paradigm in interconnects fabrication. In this paper, we discuss the most promising innovations in terms of process, materials and architectures to reduce the interconnects insulators dielectric constant.

The impact of device processing and plasma treatments at different plasma conditions on the electronic transport properties of GaN/AlGaN/GaN heterostructures was investigated as well as annealing in nitrogen atmosphere at 425°C. The electrical properties are characterized by Hall-effect measurements while electron spectroscopy and X-ray measurements are used to investigate changes in the surface chemical composition and in the layer structure, respectively. It is demonstrated that these layer structures are quite sensitive even to non-plasma based processing. Furthermore, treatments in SF6 and N2 based plasmas strongly affect the 2DEG properties of the heterostructure due to altering of the surface barrier accompanied by thinning of the layer structure. Depending on the layer structure and the plasma conditions used the electronic properties may be recovered by annealing.

CVD polycrystalline diamond surfaces were etched using reactive ion etching system with either a conventional stainless steel electrode or MgO sintered ceramic containing electrode. The micro-needle array of high aspect on diamond substrate surfaces obtained with MgO electrode was fabricated by using back-sputtering from MgO electrode. The RMS roughness of diamond substrate surfaces obtained with MgO electrode is higher than those obtained with stainless steel electrode.

This paper focuses on developing a robust process to independently control the geometrical parameters of Si nano-pillar (NP) arrays. These parameters include height and diameter of NPs, spacing between them, and the shape of the NPs. We have shown that the diameter, height, and spacing of NPs can be independently engineered by controlling the diameter of nano-beads through synthesis procedure, duration of isotropic SiO2 etching and duration of anisotropic Si etching, respectively.

Two methods to create biomimetic anti-reflection nanostructures in ordinary glass microscope object slides are presented. One technique is based on a nanosphere lithography process combined with physical vapour deposition of nickel and reactive ion etching (RIE). The other uses plasma induced dewetting of a smooth nickel surface. The amount of reflected light was measured and a method to simulate the reflectivity from an atomic force microscopy (AFM) topography scan of the glass surface is presented. The reflectivity for visible light at normal incidence was reduced to 20-50 % of the original value with both methods and the simulation gives results in good agreement to the measurement.

A novel vertical nanoporous structure is reported as a starting point for the fabrication of a fully-surround gate field effect transistor (FET) based on well-ordered nanostructures array. The proposed porous stacking is perfectly suited both for the collective organization of high density (up to 1011.cm-2) arrays of nanostructures like nanowires (NWs) or nanotubes (NTs), as with calibrated diameters (during growth), as well as for easing the Source, Gate, and Drain electrodes connections for individual or groups of nanostructures. Moreover the unique fully-surround gate architecture enables a quasi-ideal coupling between the gate and the channel, theoretically leading to improved devices performance and reduced global power consumption.

In this paper we describe the main steps for this versatile and lithography-free technique to fabricate a multi-layer porous template down to the nanometer scale, as well as the first nanostructures (carbon NTs) growth attempts inside such functional template. We highlight the fact that the proposed porous structure may acts as a passive template for the one-dimensional nanomaterials growth as well as an active element in the future device.

The proposed approach is in line with bottom-up fabrication approach to provide smaller devices, and is fully-compatible with classical processes used in the silicon industry.

Large variation in basic memory properties is a serious issue that hinders the practical use of ReRAM. This study revealed that one of the main factors causing variation is the presence of multiple filaments which have distinct set voltages in each memory cell. An operating filament switches to another filament having the smallest set voltage at each instant of switching. We propose a resistive switching model that takes the presence of multiple filaments into consideration. A Monte Carlo simulation based on the resistive switching model reproduces the set voltage distribution. Improvement of accuracy of the simulation can be also expected considering the fact that Vset increases at a certain probability at each instant of set switching.

We report on the realization of high precision hollow structures directly on silicon suitable for liquid and gas/vapor transport. The formation of hollow structures requires high aspect ratio etching combined with bulk back-side micro-machining to realize silicon-based membranes. The use of a slant angle deposition method has been used as an alternative method for three-dimensional lithography. The transfer of acetone vapor through such tiny holes shows an anomalous behavior where a sharp rise is observed followed by an exponential and gradual decay. These structures can be eventually used as mass ion separation devices.