Physical and Electrical Characteristics of HfO[sub 2] Gate Dielectrics Deposited by ALD and MOCVD

Film characteristics of gate dielectrics formed on Si(100) by atomic layer deposition (ALD) or metallorganic chemical vapor deposition (MOCVD) were investigated by atomic force microscopy, transmission electron microscopy, secondary ion mass spectroscopy (SIMS), X-ray reflectometry, ellipsometry, and electrical measurements. and water were the precursors used for ALD deposition at 300 and 370°C, whereas was used for MOCVD deposition at 550 and 650°C. Film thickness increases linearly with time for both deposition techniques. The ALD and MOCVD films have comparable density. MOCVD thin films are polycrystalline, while the 300°C deposited ALD are amorphous. The 370°C deposited ALD are polycrystalline. SIMS analysis indicated chlorine and carbon are the major contaminants in ALD and MOCVD films, respectively. Electrical properties of ALD and MOCVD films were examined using metal oxide silicon capacitors. Well-behaved capacitance-voltage and leakage current-voltage characteristics were obtained for both types of films. ALD films have slightly higher capacitance and comparable leakage when compared to MOCVD films. Room temperature and 105°C stressing of the capacitance-voltage curves showed a significant shift in the capacitance-voltage curve indicating that charge trapping was observed for all films with the 650°C deposited MOCVD showing the largest capacitance-voltage shift. Unlike MOCVD films, the capacitance-voltage characteristics of ALD films remain well behaved after stressing.