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Metal-Assisted Chemical Etching ("MacEtch") of Semiconductors Semiconductor nanostructures have become ubiquitous in consumer electronics, sensing applications, specialized and high-performance materials, and more. These structures... Read More Semiconductor nanostructures have become ubiquitous in consumer electronics, sensing applications, specialized and high-performance materials, and more. These structures are typically produced using slow, expensive, energy-intensive processes such as photolithography and chemical vapor deposition. While some of these processes have become the norm in semiconductor fabrication, the need for increasingly complex devices (and correspondingly longer multistep manufacturing roadmaps drive the need for simpler processes, such as wet chemical etching, to achieve desired semiconductor nanostructures. This suite of technologies from the University of Illinois features a scalable, semicon fab-compatible process called "metal-assisted chemical etching (MacEtch) that allows for unprecedented control of semiconductor form factors via a low-cost, energy-efficient technique. MacEtch is performed in a wet etchig environment and uses metal catalysts to selectively remove portions of semiconductor to create nanowires, pores, or a range of other form factors with various aspect ratios and dimensions. MacEtch has been demonstrated for Si, III-V, II-VI and other types of semiconductor materials. Variations of MacEtch approaches in this portfolio include an integrated superionic solid state stamping (S4) approach and a magnetic field-guided etching process that allows for even more unique form factors. MacEtch resolution is on the nanometer scale, with feature sizes often in the tens to hundreds of nanometer range. The method can be extended to form self-integrated porous low-k dielectric insulators with copper interconnects. Media https://compoundsemiconductor.net/article/121079/Revolutionising_semiconductor_etching Applications 3D nanostructure fabrication will prove useful in the areas of: Batteries, Photovoltaics, Thermoelectrics, Sensors Benefits Powerful hybrid fabrication technique (top-down approach) Fast (30 sec to a few minutes, depending on depth desired) Performed at room temperature Non-lithographical Low-Cost Scalable Efficient Fabricate both linear and annular patterns (can make circular patterns) High aspect ratios (resolution like no other technique, features down to 15nm range)
Strong, Reusable, Surface-Agnostic Adhesives via Shape Memory Polymers Surface adhesion is a ubiquitous need for consumer, manufacturing, and industrial applications. Whether hanging art on the wall, enabling pick-and-place robotics, or... Read More Surface adhesion is a ubiquitous need for consumer, manufacturing, and industrial applications. Whether hanging art on the wall, enabling pick-and-place robotics, or rapidly attaching components to a system or building, the ability to create strong, temporary seals that are reusable and do not damage surfaces is cruicial. Existing solutions based on magnets, sticky adhesives, and suction cups have limitations regarding which surfaces they can be applied to (e.g., suction cups require a smooth surface; magnets require a metallic one), how reusable they are, and how strong a bond they can form (e.g., suction cups can only achieve 1 atmosphere (atm) of adhesion in air). Researchers at the University of Illinois Urbana-Champaign have developed a two-part dry adhesive system that is strong, reusable, and capable of gripping a wide variety of smooth, rough, and non-homogenous surfaces, both flat and curved. The system features an electrically conductive layer that triggers a thermoresponsive adhesive layer; re-application of voltage allows the adhesive to be removed with no damage or loss of function to either the surface or the adhesive. This technology bonds in seconds, is residue-free, is made from inexpensive materials, does not pick up debris over time like a traditional "sticky" adhesive surface, and has been demonstrated to work on a wide variety of surfaces and environments, including underwater. The bond formed is extremely strong, with researchers showing 18 atm adhesion in initial tests. The technology has also been demonstrated in conjuction with a robotic gripper arm. Benefits Reusable Adhere to a range of surfaces, including smooth, rough, non-homogenous, non-magnetic, magnetic, fabric, etc. No damage to surface the device adheres to Waterproof Strong bond Applications Applications incude manufacturing (pick-and-place robotics that interface with a single surface of a component are often limited to materials that will respond to magnetic or suction adhesion), consumer (e.g., hanging things on walls), textiles (e.g., modifying and reusing uniforms), and myriad other industrial applications. Publication Microstructured Shape Memory Polymer Surfaces with Reversible Dry Adhesion. Jeffrey D. Eisenhaure, Tao Xie, Stephen Varghese, and Seok Kim. ACS Applied Materials & Interfaces 2013 5 (16), 7714-7717 DOI: 10.1021/am402479f
Method for Growing a Polarization Free GaN-Based Laser Diode Prof. Bayram from the University of IL has developed a method of depositing (growing) GaN on silicon substrates with complete surface coverage of cubic phase GaN. ... Read More Prof. Bayram from the University of IL has developed a method of depositing (growing) GaN on silicon substrates with complete surface coverage of cubic phase GaN. This technology provides a new method of integrating GaN photonics with silicon electronics. Applications are in light emitting diodes and transistors. Publication: Richard Liu and Can Bayram, "Aspect Ratio Optimization of cubic phase GaN on patterned silicon substrate using phase transition", Appl.Phys. Lett. To be submitted.
MacEtch Method Using CMOS Compatible catalyst TiN Dr. Xiuling Li from the University of IL has developed a new MacEtch method using TiN as the metal catalyst. Compared with conventional MacEtch catalysts,... Read More Dr. Xiuling Li from the University of IL has developed a new MacEtch method using TiN as the metal catalyst. Compared with conventional MacEtch catalysts, mostly noble metal such as Pt Au Ag, TiN has been used as insulator/adhesive layer in current CMOS production, thereby is a compatible catalyst. This method enables the combination of MacEtch with CMOS production to fabricate micro-nano structure with high-aspect ratios.
Polarization Dependent Damage-Free Laser-Assisted Plasma Etching Drs. David Ruzic and Jason Peck from the University of Illinois at Urbana-Champaign have developed a new plasma etching process assisted by a polarized pulsed laser. This... Read More Drs. David Ruzic and Jason Peck from the University of Illinois at Urbana-Champaign have developed a new plasma etching process assisted by a polarized pulsed laser. This technology addresses the need of damageless, anisotropic etching for features of 100 nm or less. It is the only known process to etch 3D structures in integrated circuits which lie along one direction, and not etch those that are perpendicular. It will enable making integrated circuits with smaller feature sizes.
Carbon Nanotube Portfolio for Manufacturing Applications This portfolio includes carbon nanotube growth and processing methods relevant to nanotube manufacturing.... Read More This portfolio includes carbon nanotube growth and processing methods relevant to nanotube manufacturing. Patterned Catalyst Techniques for Aligned Single-walled Carbon Nanotube Growth Single-walled carbon nanotubes (SWNTs) feature exceptional electric properties (conductivity and semi-conductivity) that make them attractive for nano-electronics, optics, material applications and more. This SWNT growth technology yields a dense structure without degraded alignment by eliminating undesired interactions between the SWNT and catalysts on the growth surface. More specifically, a patterned catalyst is used to provide a template to direct SWNT growth, resulting in perfectly aligned high coverage SWNTS. Benefits Higher density Large scale Higher quality Applications Patterned catalyst techniques are applicable for standard electronic devices that use thin film semiconductors, such as field effect transistors (FETs), sensors, thin-film transistors (TFTs). These devices can benefit from ability to deposit SWNT onto plastics and other unusual device substrates: steerable antenna arrays, flexible displays, etc. Medium Scale Carbon Nanotube Thin Film Integrated Circuits on Flexible Plastic Substrates This technology improves the performance and consistency of integrated circuits featuring semi-conductive carbon nanotube (CNT) transistors. Specifically, metallic conductive pathways in random nanotube networks are reduced using a medium scale carbon nanotube thin film. This process reduces these pathways by cutting fine lines into the carbon nanotube network while preserving its semiconducting properties. Benefits Reduces purely metallic conductive pathways in a carbon nanotube network used to construct electronic circuits. Vastly improves carbon nanotube device consistency in production (yield). Applications Primary application is integrated circuits for flexible substrate materials. Using Nanoscale Thermocapillary Flows to Create Arrays of Purely Semiconducting Single-Walled Carbon Nanotubes This carbon nanotube (CNT) purification technology facilitates scalable, damage-free separation of arrayed metallic and semi-conductive CNTs. Resulting CNT arrays may be large and feature high Ion/Ioff ratios, allowing for less power loss while powered off, faster switching times, and overall lower operating voltage. The invention improves CNT array quality by creating a temperature gradient to release metallic CNTs from the array matrix. Benefits Less lost power while off Faster switching time Lower operating voltage
Suite of Bioresorbable and Transient Electronics Read More Transient electronic devices belong to a set of technologies, whereby traditional analog electronic circuits and components have been made in new ways. These new electronics exist on a much smaller scale and made of bioinert or biocompatible materials. They are flexible and transient. Transient and bioresorbable technologies are a class of device that have the ability to physically disappear at a programmed rate. Inventions within this suite includedevices and processes with applications rangingfrom medicine to construction, and from defense/securityto indoor/outdoor sensors. These technologies are appropriate for applications where device placement can be costly, invasive, or inconvenient to retrieve. Features Tunable to dissolve at programmed time Bio-compatible Soft, curvilinear surface Transient battery Materials: silicon, magnesium, magnesium oxide Benefits Electronics can now be implanted on surfaces with non-planar contact patches and non-invasive integration on soft, curvilinear surfaces of biological tissues and organs. Application Areas Remaking electronics with these capabilities permits for a plethora of new applications, in medicine, environmental research, biological enhancement, digital financial transactions and traceless surveillance.
Optical Inspection of Nanoscale Structures using a Novel Machine Learning Based Synthetic Image Generation Algorithm Semiconductor defect detection using Machine Learning Dr. Goddard and Dr. Schwing have developed a machine learning technique which requires only... Read More Semiconductor defect detection using Machine Learning Dr. Goddard and Dr. Schwing have developed a machine learning technique which requires only few training images to detect and classify nano-scale anomalies in semiconductors and in noisy optical images. It is able to automate defect inspection in a 9nm semiconductor wafer with high accuracy and at a high speed in fabrication laboratories using visible light microscopy. This method is faster than atomic force microscopy and scanning electron microscopy, and is more sensitive than current optical microscopy. It can also be used for other applications such as dimension measurements and disease sample measurements. Sanyogita Purandare, Jinlong Zhu, Renjie Zhou, Gabriel Popescu, Alexander Schwing, and Lynford L. Goddard, "Optical inspection of nanoscale structures using a novel machine learning based synthetic image generation algorithm," Opt. Express 27, 17743-17762 (2019) Optical inspection of nanoscale structures using a novel machine learning based synthetic image generation algorithm. Sanyogita Purandare, Jinlong Zhu, Renjie Zhou, Gabriel Popescu, Alexander Schwing, Lynford L. GoddardOpt Express. 2019 Jun 24; 27(13): 17743–17762. doi: 10.1364/OE.27.017743

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