Ultrathin Gate and Capacitor Dielectric Formation Using Single- Wafer Processing

Abstract

ABSTRACTVarious ultrathin gate and capacitor structures were formed in a single wafer, lamp heated, reduced pressure, cold wall CVD reactor. Sequential processes including in-situ rapid thermal cleaning, surface passivation, and dielectric formation for capacitor structures was achieved at reduced pressure using pure ammonia. Three types of dielectric films were fabricated: pure thermal oxide, oxynitride, and silicon nitride. The films were grown using pure dry oxygen, nitrous oxide, and silane/ammonia chemistries, respectively. Excellent uniformity across the wafer was observed for dielectric films of different thicknesses. The RTCVD-based films exhibited improved characteristics for leakage and device drive. The TDDB data indicates that the short and long term reliability of the gate and capacitor dielectric films formed with the singlewafer process was better than that obtained with furnace-grown films. Auger electron spectroscopy and ellipsometry techniques were used to correlate film composition with processing conditions. In this paper we present the growth kinetics, composition, and thickness uniformity data and the electrical results of single-wafer processing.