The use of fine-grained polysilicon in the development of micromechanical devices (e.g. bearings, with smooth surfaces) is discussed. Fine-grained polysilicon can be produced with surface roughness near 8 AA r.m.s. (r...
详细信息
The use of fine-grained polysilicon in the development of micromechanical devices (e.g. bearings, with smooth surfaces) is discussed. Fine-grained polysilicon can be produced with surface roughness near 8 AA r.m.s. (root mean square). The ability to anneal films of this type into tension eliminates size restrictions which are caused by compressive buckling. The use of these films in micromechanical devices has been restricted because hydrogen-fluoride-etched structures are covered by an etch residue which leads to contact welding. Contact between opposing surfaces is induced mainly by surface tension effects. This problem can be avoided by removing the deflection mechanism. Thus, freezing of a water-methanol rinse after sacrificial etching all but eliminates surface tension. Removal of the ice mixture via sublimation at 0.15 mbar occurs readily. Free-standing structures with smooth surfaces and small gaps are then passivated by silicon nitride deposition or other techniques.< >
A description is given of the optimization methodology applied by the PRECISE computer program for the synthesis of analog ASICs. The application of simulation and optimization technology allows engineers to determine...
详细信息
A description is given of the optimization methodology applied by the PRECISE computer program for the synthesis of analog ASICs. The application of simulation and optimization technology allows engineers to determine easily and automatically the element values and geometries needed to reach desired or measured analog circuit performance. The integration of both technologies to determine the optimum design parameters necessary to reach circuit objectives specified by the designer is described. Optimization in AC, DC, and transient domains can occur simultaneously to account for the interdependencies of the circuit element value in those domains. In addition, the optimization process can take place in discrete and constrained design parameter space so that the technological limits are accounted for and the optimal drawn lengths and widths are manufacturable. The optimization approach can be a powerful tool for the design of analog ASICs.< >
Novel processing conditions and strain diagnostic structures are used to demonstrate that polysilicon films with built-in tensile-strain can be achieved and that any physical size limitations due to compressive-buckli...
详细信息
Novel processing conditions and strain diagnostic structures are used to demonstrate that polysilicon films with built-in tensile-strain can be achieved and that any physical size limitations due to compressive-buckling in polysilicon micromechanical structures can be eliminated.
A weighted fuzzy logic is presented in which the truth of a conjunction of propositions (or predicates) is a weighted sum of the truth of each proposition (or predicate). This is different from traditional logic where...
详细信息
A weighted fuzzy logic is presented in which the truth of a conjunction of propositions (or predicates) is a weighted sum of the truth of each proposition (or predicate). This is different from traditional logic where a conjunction would be false if only one component of the conjunction is false. The proposed logic is quite suitable for reasoning with incomplete knowledge and fuzzy retrieval or fuzzy matching. It is expected to have a very wide range of applications in knowledge engineering and many other areas. Expert systems in medical diagnosis and computer-aided design are considered as applications.< >
The processing conditions to obtain high-quality and repeatable polysilicon films are described. These include substrate preparation, the deposition procedure, reactor configuration, and postdeposition treatment. Exam...
详细信息
The processing conditions to obtain high-quality and repeatable polysilicon films are described. These include substrate preparation, the deposition procedure, reactor configuration, and postdeposition treatment. Examples of large-aspect-ratio microstructures such as long, thin beams and tuning forms for sensor applications and large-area diaphragms for piezoresistive microphones and X-ray masks are presented to illustrate the potential of polysilicon films that are in tension.< >
Calculation and measurements of Young's modulus, Poisson's ratio, shear modulus, and internal strain for fine-grained polysilicon as a function of processing conditions are presented. Calculations are based on...
详细信息
Calculation and measurements of Young's modulus, Poisson's ratio, shear modulus, and internal strain for fine-grained polysilicon as a function of processing conditions are presented. Calculations are based on appropriate averaging of single-crystal silicon properties, taking into account the film morphology. Experimental data are taken from strain diagnostic and resonant beam structures. It is found that polysilicon films can be in tension and that the intrinsic quality factor is approaching 75000.< >
The use of plasma polymerized methyl methacrylate (PPMMA) as a deep UV photoresist is described. By depositing a light sensitive polymer film from a plasma, very irregular surfaces can be coated and patterned. Other k...
详细信息
The use of plasma polymerized methyl methacrylate (PPMMA) as a deep UV photoresist is described. By depositing a light sensitive polymer film from a plasma, very irregular surfaces can be coated and patterned. Other key parameters for a photoresist are photosensitivity, stability, selectivity, and resolution. These parameters are used here as a means of optimizing the plasma process, exposure, and development cycle. The optimum process sequence results in stable films which withstand subsequent exposure to acetone and isopropyl alcohol, have a line width resolution of at least 1.5 mu m, and have a selectivity of at least 70%.< >
暂无评论