Single-wafer furnace RTCVD for silicon oxide, nitride, and oxynitride thin films

Abstract

We have developed single-wafer RTP modules for LPCVD of silicon nitride, oxynitride, oxide, and oxide/nitride/oxide (ONO) composite films. All films were deposited from dichlorosilane (DCS) as a silicon source gas. The deposition of 20-40 /spl Aring/ silicon nitride films from DCS and NH/sub 3/ showed excellent thickness uniformity. Continuous 10-wafer runs at 735/spl deg/C resulted in 40 /spl Aring/ Si/sub 3/N/sub 4/ films with within-wafer uniformity below 0.55% (1/spl sigma/) and wafer-to-wafer uniformity of 0.50% (1/spl sigma/). Conformal coverage of nitride over non-planar substrates was also demonstrated. The hot-wall reactor configuration suppresses the condensation of NH/sub 4/Cl solid byproduct. An activation energy of 1.49 eV was derived from the depositions at a reactor pressure of 0.5 Torr and DCS:NH/sub 3/ =1:3. Oxynitride films were deposited from DCS/NH/sub 3//N/sub 2/O at 800/spl deg/C. A film composition of SiO/sub 0.6/N/sub 1.1/ with a refractive index of 1.80 was obtained. Silicon dioxide (high temperature oxide, HTO) films can also be grown at 800/spl deg/C from DCS and N/sub 2/O. ONO stack films of 170 /spl Aring/ were deposited in-situ at 800/spl deg/C using sequential depositions of HTO/nitride/HTO. An Auger electron spectroscopy depth profile of the film revealed a sandwich structure of the film composition.