Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


case1054842799.pdf (4.41 MB)

ETD Abstract Container

Abstract Header

Mechanical properties of silicon films and capacitive microsensors

Ding, Xiaoyi
http://rave.ohiolink.edu/etdc/view?acc_num=case1054842799

Abstract Details

1990, Doctor of Philosophy, Case Western Reserve University, Electrical Engineering.
Experimental techniques have been developed to study the mechanical properties of boron-doped P+ silicon-films, including internal stresses and their distribution, stress-strain curve, fracture stress and Young's modulus. The necessary theoretical analyses are also presented. The internal stresses produced by boron diffusion are found to be tensile and nonuniform through the thickness of the diffused layer, which is slightly decreased by the elastic deformation and greatly relieved by the generation of dislocations. The residual stresses are measured to be about 60 MPa. They are nonuniform through the thickness of the diffused layer, and cause the cantilever beams to bend. Annealing is used to flatten the bent beams. The optimum annealing condition is 1100°C for one hour. At room temperature, the P+ silicon films are found to have linear brittle behavior, the same as bulk silicon. The maximum fracture stress and fracture strain are measured to be about 3.4 GPa and 3.6%, respectively, which is about 50% of the values corresponding to low-doping bulk silicon. The Young's modulus of P+ films measured by the RSA II and the Nanotensilometer is about 122 GPa, which is close to the value of 125 GPa determined by the resonant measurements of silicon cantilever beams. The measured You ng's modulus for P+ films is about 26% to 30% less than the measured and published values for low-doping bulk silicon. An experimental study on silicon-diaphragm buckling is given. It is found that the buckling only occurs in heavily doped diaphragms that are etched from the wafers with drive-in as the last high-temperature process. The flat diaphragms can also become buckled after annealing at high temperature. The buckled diaphragms can be flattened by going through another boron diffusion. The mechanism of the diaphragm buckling is proposed. A new mode of silicon capacitive microsensors, referred to as "touch mode sensors", is studied, in which the center area of the diaphragm is touched the substrate when certain pressure is applied. This mode of operation has more uniform sensitivity over a wide pressure range and no overload problem.
Wen Ko (Advisor)
201 p.
Mechanical properties silicon films capacitive microsensors

Recommended Citations

Citations

  • Ding, X. (1990). Mechanical properties of silicon films and capacitive microsensors [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1054842799

    APA Style (7th edition)

  • Ding, Xiaoyi. Mechanical properties of silicon films and capacitive microsensors. 1990. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1054842799.

    MLA Style (8th edition)

  • Ding, Xiaoyi. "Mechanical properties of silicon films and capacitive microsensors." Doctoral dissertation, Case Western Reserve University, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=case1054842799

    Chicago Manual of Style (17th edition)

case1054842799
941
© 1990, all rights reserved.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.