Processing and characterization of high performance gate dielectric materials by rapid photothermal process based atomic layer deposition (ALD) system.

摘要

Development of a UV and VUV assisted rapid thermal processing based atomic layer deposition (RTPALD) process is presented. The process has the inherent property of introducing less process variation than other processing techniques. The process also offers atomic level control on film growth as well as short time, low temperature processing. In-situ cleaning, in-situ deposition and in-situ annealing made this process suitable for single wafer manufacturing (SWM). Among various other high-κ materials currently being studied, ZrO2 was selected for this study, based on its material and device characteristics. RTPALD processed ZrO2 film showed a significant reduction in leakage current density as well as increase in the capacitance per unit area compared to other potential high-κ gate dielectric materials. At 1 V, ZrO2 film showed a leakage current density of 1.83 × 10−11 A/cm2 and capacitance per unit area of 8.07 μF/cm2. These values are among the best reported in the literature to date. Achieving low leakage current density along with high capacitance per unit area demonstrates the excellent performance of this process. The density of traps measured after constant current stressing showed almost no variation as the field across this film was increased up to 9 MV/cm. Electrical and structural characterizations were done on ultra thin ZrO2 samples and the results were very promising.