AVS 52nd International Symposium
    Manufacturing Science and Technology Tuesday Sessions
       Session MS-TuA

Paper MS-TuA4
Investigation of Boron Penetration through Poly Silicon Films

Tuesday, November 1, 2005, 3:00 pm, Room 207

Session: Advanced Manufacturing Processes for Silicon Devices
Presenter: X.-D. Wang, Freescale Semiconductor
Authors: X.-D. Wang, Freescale Semiconductor
W. Fan, Freescale Semiconductor
S. Phillips, Freescale Semiconductor
J. Parker, Freescale Semiconductor
S. Schauer, Freescale Semiconductor
Correspondent: Click to Email
Poly-Si is the most commonly used gate material in modern VLSI fabrication. It is also widely used as mask layer for dopant implantation. Such a process has the advantage of reducing lithography steps, however, it requires tight control on film property in order to effectively block undesired implantation through the film to the substrate silicon. In this paper, we investigate an implant issue related to boron penetration through the poly-Si film. Plan view scanning capacitance microscopy (SCM) analysis was performed to examine MOSFET devices which failed due to short channel. SCM images directly revealed undesired boron penetration in CMOS channel region to be the root cause of the failure. It was found that the yield was related to poly-Si deposition conditions. Multiple analytical techniques, including SCM, second ion mass spectroscopy (SIMS) and, transmission electron microscopy (TEM) were used to characterize the severity of boron penetration as function of film deposition conditions, especially the deposition temperature. By correlating to TEM analysis, it was found that the boron penetration is closely related to the crystalline properties of the film and optimal film growth parameters were obtained.