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U.S. Department of Energy
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As-deposited low-strain LPCVD (low-pressure, chemical-vapor-deposition) polysilicon

Technical Report ·
OSTI ID:7089341

As-deposited polysilicon films with very low residual strain (lower than 5 x 10/sup -5/) are obtained by a low-pressure, chemical-vapor-deposition (LPCVD) process. Straight polysilicon bridges 300 ..mu..m long, 1.2 ..mu..m thick, and 2 to 20 ..mu..m wide, made using this process. No buckling has been observed in any of the nearly one thousand bridges of this type made in two separate process runs. In addition, no problems of sticking between the bridges and the substrate were encountered with these structures. The polysilicon films from which the beams were fabricated were deposited by pyrolyzing silane at 605/degree/C on a phosphosilicate-glass (PSG) layer (8 wt % P). The PSG layer serves as a sacrificial layer to be subsequently etched away to free the bridge. Our research is aimed at obtaining an understanding of these relationships through consideration of the role of interfacial stresses and the kinetics of initial crystalline nucleation. The technique for producing these low-strain films is significant, however, because no high-temperature annealing steps are required to produce them. 4 refs., 4 figs.

Research Organization:
Lawrence Livermore National Lab., CA (USA); Berkeley Sensor and Actuator Center, CA (USA)
DOE Contract Number:
W-7405-ENG-48
OSTI ID:
7089341
Report Number(s):
UCRL-21092; ON: DE88016980
Country of Publication:
United States
Language:
English