The strain behavior in nanoscale patterned biaxial tensile strained Si layer on insulator is investigated in 60-nm-thick nanostructures with dimensions in the 80-400 nm range. The in-plane strain is evaluated by using UV micro-Raman. We found that less than 30% of the biaxial strain is maintained in the 200x200 nm(2) nanostructures. This relaxation, due to the formation of free surfaces, becomes more important in smaller nanostructures. The strain is completely relieved at 80 nm. This phenomenon is described based on detailed three-dimensional finite element simulations. The anisotropic relaxation in rectangular nanostructures is also discussed

A micromachined thermal emitter for fast transient temperature operation with a novel hot-plate concept is presented. This concept is based on a nonaxis-symmetric design with excellent mechanical properties during temperature modulation combined with high thermal decoupling. Especially, the mechanical stress induced by the thermal expansion of the hot-plate and their suspension was improved. This results in a reduced sensitivity for buckling of the hot-plate. The thermal emitter is fabricated using silicon on insulator (SOI) technology and KOH-etching. Different suspension structures were realized and mechanical and thermal characterizations were performed. Besides the realization of the new hot-plate suspension design, a high thermal emission at wavelengths 5 m has been achieved using ceramic coatings for emissivity enhancement. This kind of emission tuning owns-in contrast to the typical surface and bulk structuring methods-the possibility to act simultaneously as a heater passivation.

A novel micromachined thermal emitter for fast transient temperature operation is presented. Compared to most commercial available thermal emitters, the one here presented is able to operate in a pulsed mode. This allows the use of lock-in techniques or pyrodetectors in the data acquisition without the use of an optical chopper for light modulation. Therefore, these types of thermal emitters are very important for small filter photometers. Several hotplate suspension concepts were studied in order to find a design with excellent mechanical stability and high thermal decoupling. In contrary to the classical spider suspension design, a novel approach based on a non-axis-symmetric design is presented. The thermal emitters are fabricated using silicon on insulator technology and KOH-etching. The emitters are heated with Pt-meanders. For temperature determination an additional Pt-structure is deposited onto the hot-plates. The emitters are mounted in TO-5 housings using a ceramic adhesive and gold wire bonding. The used operation temperature is 750°C. In pulsed operation it's important to have a large modulation depth in terms of thermal radiation intensity in the needed spectral range. The maximal reachable modulation depth ranges from ambient temperature to steady state temperature. A modulation frequency of 5 Hz still allows using nearly the maximum modulation depth. A parameterized finite element model was realized and adapted to the measured data. This was the basis for the numerical optimization procedure for a new improved design.

A novel micromachined thermal emitter for fast transient temperature operation is presented. Most commercial available thermal emitters are not able to operate in a pulsed mode. The spider type hotplate concept promises an excellent mechanical stability together with high thermal decoupling. The thermal emitter is fabricated using silicon on insulator (SOI) technology and KOH-etching. The emitter is heated with a Pt-meander structure and the device is mounted in a TO-5 housing. Different suspensions structures as well as hotplate sizes were realized and mechanical and thermal characterizations were performed. Beside the possibility of pulsed operation, a high thermal emission at wavelengths >5 mum are achieved. Investigations on possible coatings for emissivity enhancement are the focus of the current work