Scientists Ignite Versatile Nano-Heaters for NanoRobot, NEMS, MEMS, Semiconductor, Aerospace, Automotive, Appliance and Consumer Applications--UMass Offers Tech Transfer License

Although active uses of heat to alter geometries, structures or properties in conventional processes often involve macroscale elements or systems, fundamental technical constraints can hinder comparable nanoscale approaches. For example, in structural materials, heat treatment of nanograined metals obtained by severe plastic deformation or sintering of nanopowders into bulk consolidates can be limited by in-process grain growths. 

 Generally, such limitations arise due to characteristic lengths and times of heat transfer in macroscale elements and systems, which are incompatible with spatial or temporal dimensions on the nanoscale. To date, there remains a need for elements and systems on the nanoscale that can enable both fine local heat selectivity and time-exposure control.   

Researchers from the University of Massachusetts Lowell Nanomanufacturing Center of Excellence have created nano-heater elements and systems to overcome the limitations of macroscale heaters,  The nano-heaters may be used in nanoscale manufacturing or on-board thermal actuation and for autonomous powering during operation of nanosized devices such as Micro and Nano-Electro-Mechanical Systems (MEMS & NEMS). 

In U.S. Patent Application 20090235915  University of Massachusetts Lowell professor Charalabos Doumanidis  with Claus Rebholz, Julie Chen, Teiichi Ando reveal nano-heater elements and systems that could make nanofabrication processes cheaper and more precise.  Nano-heaters could also provide a power source for nanorobots or find use in biomedical applications.   The technology is available for licensing from the University of Massachusetts Commercial Ventures and Intellectual Property (CVIP) Office. 

The nano-heater technology utilizes significant advances in nanoscience research to address the current technical constraints with thermal heating in nanomanufacturing. The collaboration between the three Universities, Northeastern University, University of Cyprus and the University of Massachusetts Lowell bring together their wealth of expertise in the area of nanotechnology. Together the scientific team has developed a technology on the nanoscale that enables local heat selectivity and time-exposure control. 

The selectivity and control of nano-heaters will lead to dramatic reduction in thermal budgets and superior processing quality in annealing, oxidation and chemical vapor deposition (CVD) of semiconductors. Thermal self-processing of electronics with layered sources patterns will obviate the compromised performance and expense of rapid thermal processing (RTP) reactors and furnaces. Up to now, the need for external connections with macroscale power supplies has negated many of the benefits of miniaturization.

The nano-heater technology has enormous implication for the future of nanotechnology. Nearly every semiconductor manufacturer in the world is working on ways to make the next generation of microprocessors cheaper by improving the yields of their manufacturing processes. In addition, the aerospace, automotive, appliance and consumer goods manufacturers are working on the next generation of the nanomaterials that will be used in their products.

 

The nano-heater technology will be a key part of their manufacturing process development. Similarly, biomedical, pharmaceutical and chemical devices using on-board thermal conditioning for sensors and processing can benefit from this technology. Applications include medical and forensic gene and drug screening arrays based on polymerase chain reaction (PCR) amplification, industrial and military biochemical detectors and patterned porous scaffolds for tissue engineering.

The ignition source can be radio frequency pulsation, plasmonic induction, microwave excitation, infrared irradiation or combinations thereof to excite the interlayer.

FIG. 1 is a representation of an exemplary nanoheater element of the invention; the first and second reactive members of the nanoheaterelement can include a layer or film comprising thicknesses, for example, of about 10 to 100 nm. FIG. 2 is an atomic force microscope (AFM) image of an exemplary interlayer of the nanoheater element in FIG. 1; FIG. 3 is a cross-section scanning electron microscope (SEM) image of the exemplary interlayer in FIG. 2; FIG. 4 is a representation of an exemplary nanoheater element of the invention.

FIG. 5A is a representation of an exemplary nanoheater system, FIG. 5B illustrates a preferred embodiment of a layered nanoheater system.

The nanoheater can be used to demonstrate nano and multi-scale thermodynamics, reaction kinetics, metallurgical and material transformations, surface science and engineering, heat transfer, electrofluidic transport and thermo and material modeling or control as well as design and manufacturing. The nanoheater system contemplates visualizing macro-scale functional rapid prototyping and scaling laws including nano or multiscale phenomena. Such visualizations can employ multi-jet modeling, three-dimensional printing and laminated object manufacturing with multiple materials such as acrylic, wax or paper and embedded ohmic heaters and thermocouples. A nanoheater element or system can also interact with conventional process controls and computer systems.

The nanoheater may be used to thermally power mechanical nanomotors and nanorobots via heating of bimetallic cantilevers for in-plane and off-plane translation and rotation or micro nanofluid pumps. The nanoheater elements or systems can also be used for electrical power generation in conjunction with thermoelectric nanocomposite materials (thermal nanobatteries), patterned electronic and optical emitter artifacts in combination with thermionic and thermoluminescent materials for nanoscale experimentation as well as chemical and biochemical temperature control, for example, in catalytic microreactors and polymerase chain reaction (PCR) DNA amplification in biodetectors and biomedical devices.

Honeywell International Reveals How to Make Nano-Resonators and MEMS Resonators

 High-Q resonators are critical components in communications and radar systems, as well as in MEMS-based sensors such as a micro-gyroscope. The combination of high-Q with small force constants enabled by nanoscale resonators can also produce resonators with exceptional force sensitivity.

FIGS. 3a and 3b show Scanning Electron Microsope (SEM) photographs of Honeywell a nano-resonator device with views after E-beam lithography and top layer pattern formation by RIE etch, (a) a disk device (b) a ring device.

Honeywell International Inc (Morristown, NJ) has developed high quality micromechanical resonators, nanoresonators and  improved high-Q nanoresonator devices.  The high quality nanoresonator devices as well as the nanofabrication tools needed to manufacture them are disclosed in U.S. Patent 20090315644.

According to Honeywell inventors Sabrina C. Sheedy James F Detry Andrzej Peczalski Chunbo Zhang  and Steven J. Eickhoff,  the nanoresonator device generally includes an input electrode, an output electrode, a nanoresonator anchored at its motionless nodal points of its resonance modes by support beam(s) and/or anchor.

The nanoresonator device can be fabricated on various wafers including a silicon on insulator (SOI) wafer, which includes an insulating layer and a heavily doped silicon layer. The nano structures with high quality factor can be patterned on a film utilizing nano fabrication tools and the patterned structures can be utilized as a mask to form permanent nano structures on the silicon layer by reactive ion etching (RIE). The insulating layer can be removed to form the anchor beams and a cavity by wet etching utilizing an etching solution.

 

Microelectromechanical systems (MEMS) include mechanical and electrical components having dimensions in the order of microns or smaller. , can be utilized in numerous applications including microsensors and microresonators. Micromechanical resonators have been widely studied for RF signal processing (e.g., oscillator, filter, and mechanical circuit) and for high-precision measurements (e.g., mass/chemical, force, position, and frequency).

Vibrating RF MEMS resonators are widely studied for frequency selection in communication sub-systems because of their high quality factor (Q) and excellent stability against thermal variations and aging. Vibrating RF MEMS resonators can replace off-chip components and improve the system size, cost and power consumption. Such resonators in sizes of ten-micron have achieved very high quality factors for example, Q up to 10,000 to 100,000 in air at MHz-GHz frequencies, and are envisioned to replace the high-Q components in existing wireless systems.

Nanoscale structures are becoming increasingly important because they provide the basis for devices with dramatically reduced power and mass, while simultaneously possessing enhanced capabilities. Nanoscale mechanical structures hold the potential to enable the fabrication of high-Q mechanical resonators with high mechanical responsivity over a wide dynamic range. Such devices can form very low-loss, low-phase-noise oscillators for filters, local oscillators, and other signal processing applications.

The resonator scaling from micro to nano size can provide significant advantages of multiple times or order of magnitude higher sensitivity, higher frequency, lower power, and higher density. The problem associated with the development of such nanoresonator (ex., nanowire resonator) is due to the reliable low-loss structure and fabrication.

Also, such nanoresonator often results in large air damping losses and anchor losses that affects Q. In addition to anchor losses, air-damping forces create more losses when operating in atmosphere and hence further reduction in Q. Low-loss microresonator structures have been demonstrated using MEMS processes. However, it is not easy to fabricate a low-loss structure in 1 um or sub micron size utilizing prior art fabrication process because of the smaller size and multiple sub-micron-alignment needs. Based on the foregoing it is believed that a need exists for an improved low-loss and high-Q nanoresonator device.

A need also exists for an improved method for fabricating the high-Q nanoresonator device as described in greater detail herein.  The nanoresonator device generally includes an input electrode, an output electrode, a nanoresonator anchored at its motionless nodal points of its resonance modes by an anchor beam. The nanoresonator device can be fabricated on a wafer, such as a silicon insulator (SOI) wafer, which includes an insulating layer and a conductive layer formed on the insulating layer. The conductive layer can be comprised of several conductive materials to include heavily doped silicon layer.

The nanoresonator can also be fabricated on other wafers with structure similar to SOI wafer, such as a wafer with top electrically-conductive layer above a middle insulation layer on the surface of a substrate. The nano structures with high quality factor can be patterned on a film utilizing nano fabrication tools and the patterned structures can be utilized as a mask to form permanent nano structures on the conductive layer of the wafer by reactive ion etching (RIE). The insulating layer can be removed to form the anchor beam and a cavity under the nano structures by wet etching utilizing an etching solution.

Figure 4 illustrates the manufacturing steps for  high quality micromechanical resonators, nanoresonators and  improved high-Q nanoresonator devices

FIG. 5 shows a photograph of a disk device after atomic layer deposition of TiO2.