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uring the deposition process and by deposition at atmospheric pressure, without sacrificing dopant uniformity or requiring additional processing steps. This paper presents data on the electrical properties and residual stress of these films and demonstrates their utility for surface micromachining applications. EXPERIMENTAL PROCEDURES Film deposition Polysilicon films were deposited in a cold-wall, vertical-geometry, RF induction-heated, atmospheric pressure chemical vapor deposition (APCVD) reactor using a single-step deposition procedure. The reaction chamber is large enough to accommodate a SiC-coated, graphite susceptor on which two 100 mm-diameter Si wafers can be mounted. Gases are injected at the top of the reactor and exhausted at the bottom. Details concerning the reactor geometry can be found in [11]. Argon is used as a carrier gas, silane (5% in H 2) as the silicon-containing precursor gas, and diborane (1000 ppm in H2) as the boron-containing doping gas. After loading the wafers and evacuating the reaction chamber, the deposition is initiated by simply backfilling the chamber with Ar at a flow rate of 2 sim. Once the chamber reaches atmospheric pressure and stable Ar flow is achieved, the susceptor temperature is raised to desired deposition temperature, and silane and diborane are injected into the Ar flow at flow rates of 300 and 200 sccm, respectively. For this study, the susceptor temperature ranged between 700'C and 955°C, as measured by an optical pyrometer. Due to thermal contact issues, the actual surface temperature of the wafer is anticipated to be lower, but to what extent is currently unknown. The primary objective of this study was to characterize the deposition of in-situ boron doped films, however, undoped films were also deposited under the same conditions without the diborane. For film characterization, the deposition time was fixed at 30 min. For device fabrication, the depositions were performed for a predetermined period, using the deposition rate data collected during the film characterization study. A variety of Si0 2-based substrate layers were used for the polysilicon depositions. For the film characterization study, Si wafers with IOOOA-thick, thermally-grown oxide films were used as substrates. For micromachining applications, low temperature oxide (LTO) films, densified at 1000°C for 30 minutes were used as sacrificial layers. In general, the properties of polysilicon deposited on the two substrates should be similar, however because the preparation of densified LTO and thermally-grown oxides differ significantly, residual stress differences in the as-deposited polysilicon films are a possibility that was not explored in this study. Film Characterization The as-deposited polysilicon films were characterized for film thickness, film stress, sheet resistance, dopant distribution, crystallinity and grain structure. In the cases of film thickness, film stress, and sheet resistance, the films were characterized on undiced wafers, allowing these properties to be mapped across the wafe