Yoshihide Senzaki

Single-Wafer Hot Wall Rapid Thermal Processing for Thin Gate Oxide Films

We have developed single-wafer furnace rapid thermal process (RTP) modules for thermal oxidation of silicon substrates. Dry oxides 20 A and wet oxides 25 A thick were grown on both 200 and 300 mm diam Si wafers with excellent thickness uniformity and repeatability. Thermal oxynitridation in nitric oxide (NO) and reoxidation can provide sub-25 A oxides. The thermal stress within the silicon wafer was maintained at low levels. It is demonstrated that high quality thin gate oxide films, comparable to those grown in a conventional furnace, can be generated without the drawbacks associated with lamp-based RTP systems.

Characterization of hot wall RTP for thin gate oxide films

We have developed single-wafer furnace RTP modules for thermal oxidation of silicon substrates. 20 /spl Aring/ dry oxide films were grown on 200 mm diameter Si wafers at 950/spl deg/C with within-wafer uniformity below 0.6% and wafer-to-wafer uniformity 0.5% (1/spl sigma/ standard deviation, 49 points with 1.5 mm edge exclusion) for 10 successive runs. Wet oxidation at 850/spl deg/C provides 25 /spl Aring/ oxide films with uniformity below 0.8% (1/spl sigma/). Thermal nitridation in nitric oxide (NO) and reoxidation can provide sub 25 /spl Aring/ oxides. For a 25 wafer repeatability experiment using 300 mm wafers, the average within wafer standard deviation of the thickness for a 20 /spl Aring/ gate oxide was 0.5% (1/spl sigma/, 49 points with 3 mm edge exclusion). The thermal stress within the silicon wafer is maintained at low levels shown with both in-situ thermal data and from post-process inspection. It is demonstrated that thin gate oxide films can be generated without the drawbacks associated with lamp based systems.

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

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.