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Polysilicon films deposited by low pressure chemical deposition (LPCVD) are the most widely used structural material for microelectromechanical systems (MEMS). However, the properties of LPCVD polysilicon are known to vary significantly, depending on deposition conditions as well as post-deposition processes. This paper presents extensive experimental results, investigating the effects of phosphorus doping and texture on Young's modulus of polysilicon films. Polysilicon films are deposited at 585, 605 and 625 to a thickness of 2 m. Specimens with varying phosphorus doping levels are prepared by diffusion doping at various temperatures and times using both and phosphosilicate glass (PSG) as the source. Young's modulus is calculated by taking the average of the values calculated from the resonant frequencies of four different-size lateral resonators. Our results show that Young's modulus decreases with increasing doping concentration, and increases with increasing texture. The polysilicon grain size and grain boundaries could also have an influence on Young's modulus, which remains to be further investigated.

WWW.POLYMERCHEMISTRY.ORG SEMICONDUCTING POLYMERSRecent studies have sought to develop intrinsically stretchable semiconducting polymers utilizing different building blocks for use in organic electronic applications. In their study reported on page 1787, Satoshi Miyane, Han-Fang Wen, Wen-Chang Chen, and Tomoya Higashihara studied the morphology of diblock (P3HT-b-P3SiHT) and triblock (P3HT-b-P3SiHT-b-P3HT) copolymers, synthesized based on Kumada catalyst-transfer polycondensation, using several methods. The cover images show the results of one such method: grazing incidence small-angle X-ray scattering (GISAXS) of a soft-polythiophene derivative, P3SiHT, one building block used in the copolymers of this study. These copolymers demonstrated improved elasticity for the semiconducting polymers.

This work proposes a method to model the non-elastic components in the fabric stretch deformation in the context of physically based fabric simulator. This paper finds that the above problem can be made tractable if we decompose the stretch deformation into the immediate elastic, viscoelastic, and plastic components. A non-trivial job is the decomposition of the deformation itself. For the purpose of the simulator development, the decomposition must be possible at any stage of deformation and any occurrence of loading and unloading. Based on the observations of various constant force creep measurements, this paper makes an assumption that, within a particular fabric, the viscoelastic and plastic components are proportional to each other and their ratio is invariant over time. Experimental results produced with the proposed method match with general expectations, and show that the method can represent the non-elastic stretch deformation for arbitrary time-varying force.