Growth of lanthanum oxide films for application as a gate dielectric in CMOS technology

MOCVD of Lanthanum Oxides from La(tmhd)3 and La(tmod)3 Precursors: A Thermal and Kinetic Investigation

“…[ 40] Thus the La 3d5/2 and La 3d3/2 features are, on the surface, resolved into two doublets centered at 834.2 eV and at 851.0 eV with a spin orbit splitting of 16.8 eV. In the bulk, the same features are slightly shifted to 833.9 eV and 850.8 eV, and the spin orbit splitting is 16.9 eV, similar to that found in La 2 O 3 .…”

“…This behavior indicates that carbonate contaminants are only due to exposure to air and not to reaction with by-products (such as CO 2 ) accompanying the precursor decomposition. Note that previous literature reports indicate that, in the presently investigated temperature range, MOCVD processes from La b-diketonate leads to films containing carbonates, [20,40] while practically carbonfree films can be obtained only by adopting atomic layer deposition (ALD) processes. [18] In the present case, carbon-free films are obtained from both precursors at lower growth rate (30 -100 nm h -1 ) compared to the previously reported processes (around 250-1000 nm h -1 ).…”

Rare-earth oxide thin films for gate dielectrics in microelectronics

“…The amount of CVD reports [69][70][71][72][73][74][75][76][77][78][79][80][81][82][83][84] available is clearly lower than in the case of PVD (Table 2). Mainly two groups of metal precursors, alkoxides (methoxy-propanolates) and ␤-diketonates have been used, while O 2 was in the most cases applied as complementary oxygen precursor.…”

“…The performance of rare-earth oxide based dielectric in MOS structures is generally analogous to that in the HfO 2 or ZrO 2 based capacitors: for instance the currents on HF-etched silicon have been in the order of 10 −5 to 10 −3 A/cm 3 , and reduced down to 10 −9 to 10 −7 A/cm 2 , if the films are grown on silicon pre-covered with chemical SiO 2 [30]. Similarly to the phenomena observed in transition metal oxides, the annealing procedure can densify rare-earth oxides, sometimes increasing the permittivity and reducing the C-V hysteresis, such as that observed in CVD La 2 O 3 films [72], or in ALD PrO x films (Fig. 2).…”

A study on the characteristics of hydrated La2O3 thin films with different oxidation gases on the various annealing temperature

“…Some binary metal oxides, such as ZrO 2 [4] and HfO 2 , [5] have been widely studied for use as gate dielectrics. In addition, rare earth metal oxides such as La 2 O 3 [6] and Y 2 O 3 [7] have been reported as next generation high dielectric constant gate dielectrics. However, rare earth metal oxides are degraded by absorption of moisture and the subsequent hydration reaction [8].…”