Process Characteristics and Physical Properties of MO-ALD ZrO2 Thin Films Deposited in a 300 mm Deposition System

Abstract

This work presents a detailed investigation of the deposition of ZrO2 using a metallorganic precursor in a 300 mm wafer processing ALD system. The ZrO2 films in this study were characterized by inline spectroscopic ellipsometry and corona-oxide-semiconductor measurements, and offline Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), Rutherford backscattering spectrometry (RBS), X-ray diffraction (XRD), and transmission electron microscopy (TEM). A growth temperature window between 215 {degree sign}C and 340 {degree sign}C was investigated and the thermal CVD rate was observed to increase above 265 {degree sign}C, thus representing an upper temperature boundary for ALD-dominated growth. For a saturated process at 265 {degree sign}C, a within-wafer non-uniformity of < 2 % for films deposited using 8 cycles or greater was obtained. An in-situ capping with TiN followed by an in-situ post-deposition rapid thermal anneal was also performed in order to assess the thermal stability of the deposited gate stack. For rapid thermal annealed films ({greater than or equal to} 900 {degree sign}C) with a TiN cap, no significant thermally-induced chemical changes were observed while a peak in the XRD spectra attributable to tetragonal and/or cubic phase ZrO2 was observed. Excellent film conformality and coverage over a FinFET structure was observed by TEM.