AVS 49th International Symposium
    Dielectrics Thursday Sessions
       Session DI+EL-ThM

Paper DI+EL-ThM11
Electrical Properties of SiO@sub 2@ Films Grown by Si(100) Reactions with Oxygen, Wet-oxygen and Wet-hydrogen

Thursday, November 7, 2002, 11:40 am, Room C-107

Session: Issues for Gate Dielectrics
Presenter: Y. Liu, Axcelis Technologies, Inc.
Authors: Y. Liu, Axcelis Technologies, Inc.
J. Hebb, Axcelis Technologies, Inc.
Correspondent: Click to Email
The oxidation of Si(100) by oxygen (O@sub 2@), wet-oxygen (H@sub 2@O+O@sub 2@) and wet-hydrogen (H@sub 2@O+H@sub 2@) is of great importance for silicon oxide (SiO@sub 2@) dielectric film formation in the advanced CMOS devices. At the atmospheric pressure and high temperatures (>1100°C), 20 to 100 Å SiO@sub 2@ films have been grown on Si(100) wafers (dia.=200 mm) using a hot-wall rapid thermal processor (Summit 200, Axcelis) enhanced with a small volume (3-liter) quartz reactor for rapid gas switching. Wet-oxygen and wet-hydrogen with controlled compositions are produced using a hydrogen-rich and an oxygen-rich catalytic water vapor generator (WVG), respectively, and are monitored in real-time with a residual gas analyzer (RGA). Kinetic equations for Si(100) reactions with oxygen and water vapor are used to control oxidation temperature, oxidant fractional pressure and time to achieve desired oxide thickness. To grow a thermal oxide film, a Si(100) wafer is rapidly heated to a desired temperature in nitrogen or hydrogen. Rapid gas sequencing is carried out to expose the wafer to oxygen, wet-oxygen or wet-hydrogen for oxidation, and back to nitrogen or hydrogen for annealing and cooling. Critical electrical properties of the thermal oxide films grown under various conditions are measured and compared systematically using a powerful and non-contact Corona Oxide Characterization of Semiconductor (COCOS) tool (FAaST, SDI). These properties include equivalent oxide thickness (EOT), oxide capacitance, flat band voltage, effective oxide charge, interface trapped charge, interface trap density, and interface trap density spectrum. Gate oxide integrity (GOI) of these films is quantified by leakage current versus voltage (I-V) and stress-induced leakage current (SILC) measurements. Correlation between growth conditions and oxide qualities will be made.