A new method for altering semiconductor properties in field effect transistors using “polarization doping.” (more...)

Carborane crosslinked silicone-based polymeric encapsulants for solid state lighting and display applications  (more...)

Researchers at the University of California, Santa Barbara have developed a novel method of producing high quality oxide/semiconductor interfaces using single chamber growth. In this method, the top oxide layers and the underlying semiconductor layers are grown in the same MOCVD reactor chamber in a single pass. No chemical pretreatments are needed on the as-grown semiconductors. The oxide/semiconductor interface is free from ambient air contaminants and is of high quality.  Using this method, total growth time for the device structures can be reduced and extensive chemical pretreatments steps are no longer needed. There is also potential for greatly enhanced output performance of the single chamber grown devices due to the higher quality oxide/semiconductor interfaces. The resulting devices will have more efficient gate modulation, less gate charge trapping, and less gate leakage currents. In addition, the single chamber approach improves the passivation of the active region of the devices, resulting in less RF-DC dispersion.  (more...)

Researchers from the UC Davis Biomedical Engineering department have developed an innovative microdevice packaging process which enable capillary-driven micron-scale self-alignment and universal nanopatternable interfacial bonding, without incurring thermal or electrical barriers. (more...)

A method for fabricating low cost, large scale, thin film substrates in the III-nitride materials family. (more...)

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As part of the Tacky Dot® donation, the University is offering for commercialization an improved method for mounting particles on a substrate having both tacky and non-tacky areas using a direct current potential This invention especially has utility for the handling and transfer of solder balls and other conductive particles to form solder bumps on the contact pads of electronic devices. (more...)

Thermoset epoxy primers and coatings are used extensively in a number of industries today. Thermoset resins have the advantage of relatively low coefficient of expansion when compared to thermoplastic coatings. They more closely match the COE of metal, thus the low differential coefficient of expansion between thermosets and metals reduces the mechanical stresses at the interface. This leads to improved durability as mechanical stresses between the coating and metal due to thermal expansion are reduced. Thermoset coatings are, however, quite brittle and must be applied in thin layers. Also, thermosets require a cure process. Thus, thermosets are excellent adhesives but do not provide an ideal coating for many applications. Although thermoplastic resins have certain advantages over thermoset epoxy resins, including being less permeable, being less brittle and requiring no cure step, they exhibit higher levels of thermal expansion that leads to higher levels of mechanical stress between coatings and the underlying metal surface. In practice, due to poor adhesion, thermoplastics have not found wide utility in the coatings industry when used without thermoset primers. (more...)

In a high-speed fabrication process for producing highly uniform ultra-small metallic micro-spheres, a molten metal is passed through a small orifice, producing a stream of molten metal. A series of molten metal droplets forms from the break up of the capillary stream. Applied harmonic disturbances are used to control and generate satellite and parent droplets. Significantly, the satellite droplets formed are smaller than the orifice, allowing for the production of smaller metal balls with larger orifices. The satellite droplets are separated from the parent droplets by electrostatic charging and deflection or by aerodynamic or acoustic sorting. Preferably, the satellite droplets are cooled before being collected to avoid defects and achieve high uniformity of the resulting metal balls. (more...)

Photolithography is the most widely used micro-fabrication technique as it is a parallel, cost effective, and high throughput process. However, conventional photolithography techniques have a resolution limit that is about half of the illumination light wavelength in free space. To date, various approaches to improve photolithography resolution have developed, but each is flawed. For example, electron-beam lithography, focused ion-beam lithography and dip-pen lithography are slow series processes not suitable for large-area pattern fabrication, and implementing reduced wavelength illumination drastically increases instrument complexity and cost. To address these problems, Researchers at UC Berkeley have developed a family of deep-subwavelength photolithography technologies. These novel technologies are based on adding an artificial metal-dielectric structure to conventional photolithography processes to fabricate reduced patterns of the conventional photolithography masks. The technique overcomes the resolution limit of the conventional photolithography and can achieve deep-subwavelength resolution comparable to that of plasmonic nanolithography and near field contact photolithography. Furthermore, it can fabricate large-area uniform patterns while plasmonic nanolithography can not. (more...)

Most micro-sensors and integrated circuits are made using silicon, and most metallic structural materials and devices are made using steel. Accordingly, the capability to bond Si-based sensors and circuits to steel-based devices and structures could lead to many potential applications. However bonding these two materials without damaging either of them is difficult. Furthermore in order to make the bonded product cost-effective, the bonding must be performed in seconds on an assembly line process. The conventional method for bonding devices to steel is by using epoxy adhesive, but the cure time is long, the modulus of elasticity is low, and the resilience in harsh environments is questionable. To address this problem, researchers at UC Berkeley have developed an innovative method for bonding silicon to steel. This method's bonding temperature is low enough to not damage the steel's heat treatment or the silicon part; and the bonding is achieved in seconds. Moreover, the bonding heat can be localized thereby reducing energy costs and possible residual heat damage. (more...)

Technological advances have allowed computer microprocessors to handle data at an extraordinary rate. However, the electrical interconnects within and between microprocessor chips introduce a severe bottle-neck to the flow of data. A promising architecture for next generation interconnects is high-speed and high-bandwidth optical interconnects, which will require heterogeneous integration of compound semiconductors with Si technologies. Some previously-explored methods for creating the optoelectronic circuitry include epitaxial growth, heteroepitaxial growth, and wafer-bonding. However, epitaxial growth of interconnections can produce large physical mismatches between desirable compound semiconductors and silicon; heteroepitaxial growth is complicated, expensive, and requires high processing temperatures that damage silicon-based circuitry; and wafer bonding is extremely susceptible to misalignments. Researchers at the University of California, Berkeley are developing advanced structures and methods for integration of compound semiconductors with conventional integrated circuit components to produce various active and passive optoelectronic components for optical interconnects, sensors, semiconductor lasers and other devices. The structures can accommodate quantum wells or quantum dots. The method under development at Berkeley will eliminate problems with alignment and processing temperature that constrain the application of conventional methods for fabricating optoelectronic circuitry. (more...)

The objective of molecular imprinting is to create solid materials containing chemical functionalities that are spatially organized by interactions with imprint (or template) molecules during the synthesis process. Subsequent removal of the imprint molecules leaves behind designed sites for the recognition of small molecules, making the material ideally suited for applications such as separations, chemical sensing and catalysis. A significant limitation to the use of bulk imprinted silica in catalytic applications has been due to the hydrophobic framework resulting from the materials synthesis process. Researchers at the University of California, Berkeley have developed a process for synthesizing a new class of bulk imprinted silicates with a hydrophilic framework, which circumvents these limitations. Imprinted sites consisting of up to two primary amines have been synthesized within hydrophilic microporous and mesoporous inorganic-oxide frameworks. The preparation of bulk-imprinted silicas is a step toward the development of imprinting as a general strategy for synthesizing materials-by-design. (more...)

Researchers at the University of California, Berkeley have developed highly sensitive ultraviolet light sensors based on zinc oxide nanowires. Upon exposure to light of wavelength below 400 nm, the electrical resistivity of the semiconducting nanowires decreases by 4-5 orders of magnitude. ?Nanowire UV photodetector and optical switches?, H. Kind, H. Yan, M. Law, B. Messer, P. Yang, Adv. Mater. 14, 158, 2002 (more...)

Researchers at the University of California, Berkeley have applied the principles of intermolecular attractive forces to develop nano-structures with extraordinary adhesive properties. These biomimetically inspired nano-structures can stick to wet, dry, rough or smooth surfaces, and can be peeled-off and re-used; they are also self-cleaning, leave no residue, and are bio-compatible. The original research was published in Nature (2000.405:681-5) and PNAS (2002.99:12252-6). The University has filed US and international patent applications that broadly cover this inventive concept as well as its manufacturing methods and end-user applications. (more...)

Implantable Active Prosthetic Devices and Methods for Animation of Paralyzed Tissues (more...)