Dry Etching Research Articles

(Invited) Fabrication and Device Performance of 2.7 Kv/2.5A NiO/Ga2O3 Heterojunction Power Rectifiers

In this study, The fabrication of a p-n junction NiO/Ga2O3 rectifier in which we employ a bilayer NiO structure with two different doping levels to achieve both high breakdown voltage and low on-state resistance was described. The band alignment of the NiO to the Ga2O3 was measured. Selective wet and dry etch processes for removing NiO from the underlying Ga2O3 was developed. Finally, the dc and switching performance of the rectifiers was characterized. The maximum breakdown voltage was 2.7 kV for a 1 mm diameter rectifier, with 2.5 A forward current and on/off ratio > 108 over a broad range of switching voltages. The reverse recovery time was limited by the measurement circuit but was < 100 µs. These results show the promise of heterojunction rectifiers based on Ga2O3 for future generations of power switching applications. Figure 1

Study on effective dry etching of InGaZnO thin films under capacitively coupled plasma-reactive ion etching with a nonfluorine-based etching gas

Dry etching of InGaZnO (IGZO) thin films was performed in a capacitively coupled plasma-reactive ion etching (CCP-RIE) mode using hydrochloride (HCl) and argon (Ar) gases. Dry-etching characteristics and surface properties of IGZO films were then investigated according to gas mixture ratio, radio frequency power, and chamber working pressure. With an optimized ratio of HCl : Ar at 20 : 20 SCCM, the IGZO film showed good etch characteristics with a moderate etch rate of 6.0 nm/min and a low roughness of 0.19 nm. During the etching process of IGZO thin films, nonvolatile by-products such as GaClx, InClx, and ZnClx generated on the surface could be effectively removed by physical bombardment with Ar+ ions. As a result, we successfully conducted dry etching of IGZO thin films in the CCP-RIE system under HCl-Ar gas conditions, which demonstrated dry etching on IGZO without needing a fluorine-based etching gas.

Comparison between etching techniques for solid-state nuclear track detector (CN-85) to develop alpha tracks

The present work aims to estimate and compare the etching parameters of Solid-state nuclear track detector (SSNTD) CN-85 with different etching techniques (Water bath, Ultrasound, Microwave, Oven and Plasma (Dry Etching)). CN-85 detectors were exposed in a direct contact to the sensitive face (notated face) for 15 s to alpha particles emitted from the radium-226 source (226Ra) of 4.87 MeV energy and 5 μCi activity. Small pieces with area (1 × 1) cm2 of CN-85 detectors were used. Using an optical microscope (model, N-200M). It has magnification of 400× to count the alpha tracks of CN-85 detectors. Tracks density and tracks diameters of CN-85 detector at different etching time from the five etching techniques were estimated. In addition, based on the experimental results, etching parameters related to the maximum track densities for CN-85 track detector are calculated. With etching efficiency value of ∼ 73%, microwave technique is the most efficient technique follow with plasma technique with (∼59%). The other three techniques had efficiencies three times less than microwave technique. Therefore, it can conclude that microwave etching technique is recommended for CN-85 detectors.

Hydrophobic and oleophobic nanopillars reduce viscous drag in slit nanofluidic channels

Nanofluidics exploiting 100 nm nanochannels has developed, and ultrasmall analytical applications in single-molecule level are expected. However, with downscaling the channel size, the required external pressure for driving liquids becomes exceedingly high due to increased fluid resistance and causes a problem to miniaturize a fluidic system. In the present study, we developed a drag reduction method of slit nanochannels with micrometers-width and nanometers-depth for both aqueous and organic reagents by integrating hydrophobic and oleophobic nanostructured surface. A fabrication process based on electron beam lithography and dry etching was established to realize inverted-trapezoidal shaped hydrophobically modified nanopillars with 300 nm width and 210 nm height on a fused-silica substrate. We optimized the geometry of nanopillars, and those with an upper base angle of 78° and an interval of 400 nm induced hydrophobic property for water with a contact angle of 139° and also oleophobic property for hexadecane with that of 108° by the Cassie–Baxter state with the pinning effect. By integrating the nanopillars, drag reduction of slit nanochannels for both water and hexadecane by slipping with the gas–liquid interface at the nanopillar interval was achieved with apparent slip lengths of 269 nm (water) and 108 nm (hexadecane). The drag reduction rate increased with decreasing the channel depth, and for a nanochannel with 208 nm depth, rates of 87% (water) and 80% (hexadecane) were achieved. We demonstrated miniaturization and energy saving of nanofluidic system based on the developed method. This work will greatly contribute to advancement of nanofluidics and engineering for dust proof materials.

Effect of Post-Etch Wet Cleaning on GaAs Surfaces

In this study, we investigated the effect of the post-etch cleaning of GaAs surfaces. We found that a plasma damage layer was formed on GaAs surfaces by dry etching, and an As-rich layer remained after post-etch cleaning. The As rich layer needs to be removed because it is replaced by micron-sized particles when stored in an air. We also found that a pure GaAs surface can be obtained by performing additional cleaning consisting of oxide formation and removal.

On Gas-Phase Selective Dry Etching in 3D Inflections

Semiconductor industry periodically goes through major transitions in the architectures and materials. The previous such transition was the Logic transition to FinFET and NAND transition to 3DNAND that revolutionized the two devices and accelerated PPAC (power, performance, area, cost) progress. Over the last decade, introduction of EUV lithography has driven the device miniaturization and furthered the cause of PPAC, but with the same architecture. The accelerating technological needs at lower cost point with better power efficiency are driving the current push in fundamental architectural changes and new materials introductions, especially in Logic and DRAM with a transition to 3D structures. This moves the critical etches from traditional RIE to selective isotropic etching. Furthermore, newer materials and requirements of better interfaces in these 3D structures are driving the need for dry selective treatments with good isotropicity and free of damage. This paper will give an overview of the current state of selective dry etch and progress in treatments.

Plasma Oxidation of Patterned Mo Nanowires for Precise and Uniform Dry Etching

We demonstrate that a uniform recess of polycrystalline Mo can be achieved using a two-step method: metal oxidation with isotropic oxygen plasma that forms a layer of MoO3 and selective etching of this oxide layer. The oxidation step fully defines the recess depth, and its uniformity is ensured by the low facet dependence of plasma oxidation. We have extensively studied the oxidation of patterned Mo nanowires (30 nm width) in isotropic oxygen plasma and achieved uniform oxide layers of predefined thickness by controlling radio-frequency (RF) power, gas pressure, and exposure time. We showed that using highly selective oxide etching, we can perform multiple etching cycles with a typical etch rate of 1-2 nm per cycle, depending on the RF power. Due to plasma isotropy, this approach can be implemented for a controlled uniform etching of large vertical stacks of metal nanostructures.

High density lithium niobate photonic integrated circuits

Photonic integrated circuits have the potential to pervade into multiple applications traditionally limited to bulk optics. Of particular interest for new applications are ferroelectrics such as Lithium Niobate, which exhibit a large Pockels effect, but are difficult to process via dry etching. Here we demonstrate that diamond-like carbon (DLC) is a superior material for the manufacturing of photonic integrated circuits based on ferroelectrics, specifically LiNbO3. Using DLC as a hard mask, we demonstrate the fabrication of deeply etched, tightly confining, low loss waveguides with losses as low as 4 dB/m. In contrast to widely employed ridge waveguides, this approach benefits from a more than one order of magnitude higher area integration density while maintaining efficient electro-optical modulation, low loss, and offering a route for efficient optical fiber interfaces. As a proof of concept, we demonstrate a III-V/LiNbO3 based laser with sub-kHz intrinsic linewidth and tuning rate of 0.7 PHz/s with excellent linearity and CMOS-compatible driving voltage. We also demonstrated a MZM modulator with a 1.73 cm length and a halfwave voltage of 1.94 V.

Atomic layer etching (ALE) of III-nitrides

Atomic layer etching (ALE) was performed on (Al, In, Ga)N thin films using a cyclic process of alternating Cl2 gas absorption and Ar+ ion bombardment in an inductively coupled plasma etcher system. The etch damage was characterized by comparing photoluminescence of blue single quantum well light-emitting diodes before and after the etch as well as bulk resistivities of etched p-doped layers. It was found that etched surfaces were smooth and highly conformal, retaining the step-terrace features of the as-grown surface, thus realizing ALE. Longer exposures to the dry etching increased the bulk resistivity of etched surfaces layers slightly, with a damaged depth of ∼55 nm. With further optimization and damage recovery, ALE is a promising candidate for controlled etching with atomic accuracy. It was found that Al0.1Ga0.9N acts as an etch barrier for the ALE etch, making it a suitable etch to reveal buried V-defects in III-nitride light emitting diodes.

Engineering Refractive Index Contrast in Thin Film Barium Titanate-on-Insulator.

Barium titanate-on-insulator has demonstrated excellent vertical optical confinement, low loss, and strong electro-optic properties. To fabricate a waveguide-based device, a region of higher refractive index must be created to confine a propagating mode, one way of which is through dry etching to form a ridge. However, despite recent progress achieved in etching barium titanate and similar materials, the sidewall and surface roughness resulting from the physical etching typically used limit the achievable ridge depth. This motivates the exploration of etch-free methods to achieve the required index contrast. Here, we introduce three etch-free methods to create a refractive index contrast in barium titanate-on-insulator, including a metal diffusion method, proton beam irradiation method, and crystallinity control method. Notably, molybdenum-diffused barium titanate leads to a large index change of up to 0.17. The methods provided in this work can be further developed to fabricate various on-chip barium titanate optical waveguide-based devices.

Wafer-Scale Monolithic Integration of Blue Micro-Light-Emitting Diodes and Green/Red Quantum Dots for Full-Color Displays

We demonstrated a simple method for achieving green and red colors by patterning quantum dots (QDs) on GaN-based blue micro-light-emitting diodes (μLEDs) using standard photolithography and dry etching process. The QDs could be patterned as small as 2 μm in size on a 4-inch wafer, revealing the ultra-high resolution and throughput capability of this method. The individual color-converted green and red μLEDs in a size of 10 μm × 10 μm exhibited a peak external quantum efficiency (EQE) of 9.6% and 14.7%, respectively. We also achieved the monolithic integration of red, green, and blue (RGB) μLEDs as a single pixel by sequentially patterning red and green QDs. The color gamut of the RGB μLEDs covered 83.4% of the Rec. 2020 color space in the CIE 1931 diagram. This method is very effective for patterning color-converted QDs with down to 2μm-size-resolution and achieving high performance for red/green μLEDs, while enabling scalable fabrication of full-color μLED displays.

Micro Electro Mechanical Systems (MEMS): Fabrication Using DEMATEL Method

microelectromechanical systems (mems): fabrication Introduction: Micro-electromechanical systems (mems) are mechanical and small for connecting electrical components and integrated devices or used to create systems a process is a technology. They are integrated circuits (ic). Batch processing techniques fabricated using a few micrometers to millimeters will be up to of the smallest machines energy, the technology that can create them appreciated before existence, for example, Richard Feynman's The famous 1959 lecture there is plenty of room at the bottom. Mems are modified semiconductor device fabrication using technologies once fabricated, the practice came electronics in general used for making, molding, and plating, wet etching (Koh, tmah), and dry etching machine (EDM) and small ability to manufacture devices other technologies with. Research significance: Micro-electro-mechanical systems or mems stands for technology, it's formed using microfabrication techniques in a general form small mechanical and electro mechanical components viz devices and structures can be defined as mems devices important physical dimensions at the lower end of the dimension spectrum many from below one micron varies up to millimeters. Likewise, mems device types, with no moving parts from very simple structures integrated microelectronics multiple moving components under control containing highly complex electro as far as mechanical systems vary. A core of mems the criterion is, at least some elements types of mechanical operations contain, these organs move can it or not? Define mems the term used is that of the world it varies in different regions. In the united states, they are mainly called mems, at the same time some other parts of the world in areas they are “microsystems technology” or “micro machines called devices”. Functional components of mems miniaturized structures, sensors, and actuators, and although microelectronics, very remarkable and very interesting elements are micro-sensors and micro-actuators micro sensors and micro actuators are "transducers". Are properly classified as they are from a form of energy converted to another format and are defined as devices. In micro sensors, the device generally measured mechanical converts signal into an electrical signal. Methodology: the decision-making trial and evaluation laboratory (dematel) is regarded as an efficient technique for locating the causal links in a complex system. It focuses on assessing the interdependencies between elements and identifying the crucial ones using a visual structural model. Alternative: electrical, magnetic, mechanical, thermal, chemical Evaluation preference: electrical, magnetic, mechanical, thermal, chemical Results: from the result, it is seen that electrical got the first rank whereas the thermal is having the lowest rank. Conclusion: as can be seen, electrical has the lowest rating while thermal has the top rank.

Neuroevolution-Based Network Architecture Evolution in Semiconductor Manufacturing.

Promoted model architectures or algorithms are crucial for intelligent manufacturing since developing them takes a lot of trial and error to embed the domain knowledge into the models correctly. Especially in semiconductor manufacturing, the whole processes depend on complicated physical equations and sophisticated fine-tuning. Therefore, we use a neuroevolution-based model to search the optimized architecture automatically. The collector current value at a particular bias of the silicon-germanium (SiGe) heterojunction bipolar transistor, generated by technology computer-aided design (TCAD), is used as the target dataset with six process parameters as the inputs. The processes include oxidation, dry and wet etching, implantation, annealing, diffusion, and chemical-mechanical polishing. Our work can build a suitable model network with a fast turnaround time, and practical physical constraints are fused in it without domain knowledge extraction. Take the case with 3840 data and one output as an instance. The mean square errors of the train set and validation set, as well as the mean absolute percentage error of the test set, are 1.317 × 10-6, 7.215 × 10-7, and 0.216 while using multilayer perceptron (MLP) and they are 3.285 × 10-7, 1.661 × 10-7, and 0.097 while using NE. The consequences show that the work in this vein is promising. According to the trend plot and results, the ability to extract physic is much better than the traditional (MLP) model.

Study of Selective Dry Etching Effects of 15-Cycle Si0.7Ge0.3/Si Multilayer Structure in Gate-All-Around Transistor Process.

Gate-all-around (GAA) structures are important for future logic devices and 3D-DRAM. Inner-spacer cavity etching and channel release both require selective etching of Si0.7Ge0.3. Increasing the number of channel-stacking layers is an effective way to improve device current-driving capability and storage density. Previous work investigated ICP selective etching of a three-cycle Si0.7Ge0.3/Si multilayer structure and the related etching effects. This study focuses on the dry etching of a 15-cycle Si0.7Ge0.3/Si multilayer structure and the associated etching effects, using simulation and experimentation. The simulation predicts the random effect of lateral etching depth and the asymmetric effect of silicon nanosheet damage on the edge, both of which are verified by experiments. Furthermore, the study experimentally investigates the influence and mechanism of pressure, power, and other parameters on the etching results. Research on these etching effects and mechanisms will provide important points of reference for the dry selective etching of Si0.7Ge0.3 in GAA structures.

Impact of the W etching process on the resistive switching properties of TiN/Ti/HfO2/W memristors

In this work, we investigate the effects related to the etching process of the W bottom electrode (BE) on the breakdown voltages and the resistive switching (RS) characteristics of TiN/Ti/HfO2/W memristors. Two different W-BE etching processes are compared: anisotropic dry etching and isotropic wet etching. In order to complete the analysis, scanning electron microscope inspections are used to investigate the profile of the patterned BE. Finally, the hysteretic current–voltage (I-V) characteristics are simulated using the Dynamic Memdiode Model (DMM).

3D modeling of feature-scale fluorocarbon plasma etching in silica

Fluorocarbon dry etching of vertical silica-based structures is essential to the fabrication of advanced complementary metal-oxide-semiconductor and dynamic random access memory devices. However, the development of etching technology is challenged by the lack of understanding of complex surface reaction mechanisms and by the intricacy of etchant flux distribution on the feature-scale. To study these effects, we present a three-dimensional, TCAD-compatible, feature-scale modeling methodology. The methodology combines a level-set topography engine, Langmuir kinetics surface reaction modeling, and a combination of reactant flux evaluation schemes. We calibrate and evaluate our model to a novel, highly selective, etching process of a mathrm {SiO_2} via and a textrm{Ru} hardmask by mathrm {CF_4/C_4F_8}. We adapt our surface reaction model to the novel stack of materials, and we are able to accurately reproduce the etch rates, topography, and critical dimensions of the reported experiments. Our methodology is therefore able to prototype and study novel etching processes and can be integrated into process-aware three-dimensional device simulation workflows.

Etching of scandium-doped aluminum nitride using inductively coupled plasma dry etch and tetramethyl ammonium hydroxide

Etching of scandium-doped aluminum nitride using inductively coupled plasma dry etch and tetramethyl ammonium hydroxide

Xenon Difluoride Dry Etching for the Microfabrication of Solid Microneedles as a Potential Strategy in Transdermal Drug Delivery (Small 27/2023)

Xenon Difluoride Dry Etching for the Microfabrication of Solid Microneedles as a Potential Strategy in Transdermal Drug Delivery (Small 27/2023)

Terahertz bandpass filter with Babinet complementary metamaterial mirrors and silicon subwavelength structure.

We fabricated a rigid bandpass filter with a broad far-infrared wavelength range of high transmission using a silicon subwavelength structure with a Babinet complementary metamaterial half-mirror pair, despite its apparent light-blocking structure. The rigid one-piece filter was produced by a simple process involving photolithography, dry etching, and deposition, each performed only once. The transmission principle relies on the Fabry-Perot resonance with a metamaterial half-mirror pair that exhibits extraordinary optical transmission due to spoof surface plasmon polaritons. The transmission center wavelength was successfully predicted by the basic equation of Fabry-Perot resonance with an effective medium approximation. In contrast, a narrower bandwidth and a lower minimum transmittance than those predicted from the basic equation were provided by the subwavelength Si structure between the metamaterial mirrors, resulting in enhanced bandpass filter characteristics.

Ultra-Wideband Mid-Infrared Chalcogenide Suspended Nanorib Waveguide Gas Sensors with Exceptionally High External Confinement Factor beyond Free-Space.

On-chip waveguide sensors are potential candidates for deep-space exploration because of their high integration and low power consumption. Since the fundamental absorption of most gas molecules exists in the mid-infrared (e.g., 3-12 μm), it is of great significance to fabricate wideband mid-infrared sensors with high external confinement factor (ECF). To overcome the limited transparency window and strong waveguide dispersion, a chalcogenide suspended nanorib waveguide sensor was proposed for ultra-wideband mid-infrared gas sensing, and three waveguide sensors (WG1-WG3) with optimized dimensions exhibit a wide waveband of 3.2-5.6 μm, 5.4-8.2 μm, and 8.1-11.5 μm with exceptionally high ECFs of 107-116%, 107-116%, and 116-128%, respectively. The waveguide sensors were fabricated by a two-step lift-off method without dry etching to reduce the process complexity. Experimental ECFs of 112%, 110%, and 110% were obtained at 3.291 μm, 4.319 μm, and 7.625 μm, respectively, through methane (CH4) and carbon dioxide (CO2) measurements. A limit of detection of 5.9 ppm was achieved for an averaging time of 64.2 s through the Allan deviation analysis of CH4 at 3.291 μm, leading to a comparable noise equivalent absorption sensitivity of 2.3 × 10-5 cm-1 Hz-1/2 as compared to the hollow-core fiber and on-chip gas sensors.