An object is to provide a semiconductor device of which a manufacturing process is not complicated and by which cost can be suppressed, by forming a thin film transistor using an oxide semiconductor film typified by zinc oxide, and a manufacturing method thereof. For the semiconductor device, a gate electrode is formed over a substrate; a gate insulating film is formed covering the gate electrode; an oxide semiconductor film is formed over the gate insulating film; and a first conductive film and a second conductive film are formed over the oxide semiconductor film. The oxide semiconductor film has at least a crystallized region in a channel region.

Semiconductor device, and manufacturing method thereof

SUMMARY A solution procedure for the analysis of planar and axisymmetric contact problems involving sticking, frictional sliding and separation under large deformations is presented. The contact conditions are imposed using the total potential of the contact forces with the geometric compatibility conditions, which leads to contact system matrices and force vectors. Some key aspects of the procedure arc the contact matrices, the use of distributed tractions on the contact segments for deciding whether a node is sticking, sliding or releasing and the evaluation of the nodal point contact forces. The solutions to various sample problems are presented to demonstrate the applicability of the algorithm. Much progress has been made during recent years in the development of computational capabilities for general analysis of certain nonlinear effects in solids and structures. In each of these developments, quite naturally, the first step was the demonstration of some ideas and possibilities for the analyses under consideration, and then the research and development for reliable and general techniques was undertaken. The second step proved in many cases much more difficult, and in the case of capabilities for analysis of contact problems has yielded few general results. Although some of the first complex contact problems have been solved using the finite element method quite some time ago,'- and much interest exists in the research and solution of contact problems (see, for example, References 4-1 5), there is still a great deaiwf effort necessary for the development of a reliable, general and cost-effective algorithm for the practical analysis of such problems. This is largely due to the fact that the analysis of contact problems is computationally extremely difficult, even for the simplest constitutive relations used. Much of the difficulty lies in that the boundary conditions of the bodies under consideration are not known prior to the analysis, but they depend on the solution variables. The aim in our research is the development of a solution algorithm for analysis of general contact conditions which shall include the possibilities to analyse: contact between flexible-flexible and rigid--flexible bodies; sticking or sliding conditions (with or without friction); large relative motions between bodies; repeated contact and separation between the bodies. Since the large deformation motion of the individual bodies can in many cases be analysed already quite effectively,'6 an algorithm of the above nature will certainly enlarge, very

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A solution method for planar and axisymmetric contact problems

Metal silicides have played an indispensable role in the rapid developments of microelectronics since PtSi was first used to improve the rectifying characteristics of diodes in early 1960s. This wo ...

Metal silicides in CMOS technology : Past, present, and future trends

An object is to provide a method for manufacturing a semiconductor device, in which the number of photolithography steps can be reduced, the manufacturing process can be simplified, and manufacturing can be performed with high yield at low cost A method for manufacturing a semiconductor device includes the following steps: forming a semiconductor film; irradiating a laser beam by passing the laser beam through a photomask including a shield for shielding the laser beam; subliming a region which has been irradiated with the laser beam through a region in which the shield is not formed in the photomask in the semiconductor film; forming an island-shaped semiconductor film in such a way that a region which is not irradiated with the laser beam is not sublimed because it is a region in which the shield is formed in the photomask; forming a first electrode which is one of a source electrode and a drain electrode and a second electrode which is the other one of the source electrode and the drain electrode; forming a gate insulating film; and forming a gate electrode over the gate insulating film

Method for Manufacturing Semiconductor Device

A phase-change memory may be formed with at least two phase-change material layers separated by a barrier layer. The use of more than one phase-change layer enables a reduction in the programming volume while still providing adequate thermal insulation.

Multiple layer phase-change memory

The use of contacting components such as gear teeth in mesh and shrink-fitted shafts is very common in engineering practice. This paper deals with the development of a theoretical method which gives a solution for non-linear contact problems with irreversibility resulting from stick-slip phenomenon.



The method is based on the finite element method and load incremental theory. The geometrical and the statical boundary conditions on contact surfaces are treated as additional conditions being independent of stiffness equations. As a result, the algorithm of calculation is simplified and only a part of the simultaneous equations related to the contact surfaces is required to be solved instead of the overall stiffness equations at each step. Furthermore, the magnitude of load causing a change in a contact condition of one contact nodepair is taken as a load increment, in analogy with the incremental iterative procedure for elastic-plastic problems. Therefore, the method provides a general and efficient method for analysis and design of such problems.



As illustrative examples, the stick-slip behaviour of turbo-alternator end-bells and other problems are discussed. The calculated results show a reasonable agreement with experimental data and other solutions.

Finite element incremental contact analysis with various frictional conditions

With the present gap between CAD and CAE, designers are often hindere in their efforts to explore design alternatives and ensure product robustness. This paper describes the multi-representation architecture (MRA)—a design-analysis integration strategy that views CAD-CAE integration as an information-intensive mapping between design models and analysis models. The MRA divides this mapping into subproblems using four information representations: solution method models (SMMs), analysis building blocks (ABBs), product models (PMs), and product model-based analysis models (PBAMs). A key distinction is the explicit representation of design-analysis associativity as PM-ABB idealization linkages that are contained in PBAMs. The MRA achieves flexibility by supporting different solution tools and design tools, and by accommodating analysis models of diverse discipline, complexity and solution method. Object and constraint graph techniques provide modularity and rich semantics. Priority has been given to the class of problems termedroutine analysis—the regular use of established analysis models in product design. Representative solder joint fatigue case studies demonstrate that the MRA enables highly automated routine analysis for mixed formula-based and finite element-based models. Accordingly, one can employ the MRA and associated methodology to create specialized CAE tools that utilize both design information and general purpose solution tools.

http://www.eislab.gatech.edu/pubs/journals/ewc-mra/ewc-mra.pdf

Integrating Engineering Design and Analysis Using a Multi-Representation Approach †

Residual stress change in silicon thin films during crystallization of amorphous silicon is discussed experimentally by detecting the wafer curvature change using a scanning laser microscope. The as‐deposited amorphous‐silicon film shows compressive stress of about 200 MPa. During a crystallization reaction at about 650 °C, a large tensile stress of about 1000 MPa develops in the film due to film shrinkage. The final residual stress of polycrystalline film depends on the film formation process.

Crystallization-induced stress in silicon thin films

Prevention of reduction in the production yield due to the increase in the area of a semiconductor chip permits a sophisticated-performance single-chip semiconductor device to be fabricated. This also permits a many-kind small-amount production of semiconductor devices to be implemented. After plural semiconductor chips 2 and 3 are fabricated separately, only defect-free chips of them are selected. The selected defect-free chips are connected in contact between their side walls of their densest faces of atoms of their substrates so that the surfaces 4a and 4b where elements are to be formed are located in the same plane. Thus, even when the chip area is increased, reduction of the production yield can be prevented, thereby permitting a large-area sophisticated-performance single chip semiconductor device to be fabricated. If many kinds of semiconductor chips are prepared and connected in their combination in a variety of forms, it is possible to realize a many-kind small-amount production of semiconductor devices.

Semiconductor device having plural chips with the sides of the chips in face-to-face contact with each other in the same crystal plane

In forming an electrode 2 on a silicon oxide film 5 on a semiconductor substrate 4 through a silicon oxide film 5, for example, the gate electrode 2 is structured in a laminated structure of a plurality of polycrystalline silicon layers 6. The portion of the gate electrode 2 is formed by a method of manufacturing a thin film having a process of depositing amorphous layers and a process of crystallizing (recrystallizing) this amorphous material. In this case, depositing of the amorphous layers is carried out dividedly by a plurality of times so that the thickness of an amorphous layer to be deposited at one time is not larger than a thickness to be prescribed by a critical stress value determined according to a fail event, the amorphous material is crystallized after each process of depositing each amorphous layer has been finished, and the process of depositing amorphous layers and the process of crystallizing the amorphous material are repeated, whereby a laminated structure of the polycrystalline layer 6 having a necessary film thickness is obtained. With the above-described arrangement, it is possible to prevent a deterioration of electric characteristics of a semiconductor device and an occurrence of a defect, such as a peeling off between layers, cracks in a layer, etc., and it is possible to obtain a polycrystalline layer of small grain size in a desired film thickness by a lamination of polycrystalline materials.

Noriaki Okamoto

Papers

Finite element incremental contact analysis with various frictional conditions

Integrating Engineering Design and Analysis Using a Multi-Representation Approach †

Crystallization-induced stress in silicon thin films

Semiconductor device having plural chips with the sides of the chips in face-to-face contact with each other in the same crystal plane

Semiconductor apparatus having conductive thin films and manufacturing apparatus therefor