IR study of fundamental chemical reactions in atomic layer deposition of HfO2 with tetrakis(ethylmethylamino)hafnium (TEMAH), ozone, and water vapor

The fundamental reactions in HfO2 atomic layer deposition (ALD) with the precursors tetrakis(ethylmethylamino)hafnium (TEMAH), ozone, and water vapor on Si (1 0 0) surfaces at room temperature (RT) were studied by infrared absorption spectroscopy (IRAS) with a multiple internal reflection geometry. The IRAS results indicated that TEMAH can be adsorbed at OH sites on Si surfaces at RT. Ozone irradiation on the TEMAH-adsorbed Si surface at RT effectively removes hydroaminocarbon adsorbates introduced in the course of TEMAH adsorption, although this treatment provides no OH-group adsorption sites for TEMAH on the Si surface at RT. For further adsorption, water–vapor treatment at around 160 °C is effective in restoring the adsorption sites. The IR study suggests that the cyclic process of TEMAH adsorption and ozone treatment at RT followed by OH restoration with water vapor at a temperature of 160 °C allows continuous HfO2 deposition.