The atomic layer deposition (ALD) growth of Er x Ga 22x O 3 (0 ¡ x ¡ 2) thin films was demonstrated using two precursor systems: Er(thd) 3 , Ga(acac) 3 , and ozone and Er(C 5 H 4 Me) 3 , Ga 2 (NMe 2 ) 6 , and water at substrate temperatures of 350 and 250 uC, respectively. Both processes provided uniform films and exhibited surface-limited ALD growth. The value of x in Er x Ga 22x O 3 was easily varied by selecting a pulse sequence with an appropriate erbium to gallium precursor ratio. The Er(thd) 3 , Ga(acac) 3 , and ozone precursor system provided stoichiometric Er x Ga 22x O 3 films with carbon, hydrogen, nitrogen, and fluorine levels of ,0.2, ,0.2, ,0.3, and 0.6-2.2 atomic percent, respectively, as determined by Rutherford backscattering spectrometry (RBS) and time of flight-elastic recoil detection analysis (TOF-ERDA). The film growth rate was between 0.25 and 0.28 A ˚cycle 21 . The effective permittivity of representative samples was between 10.8 and 11.3. The Er(C 5 H 4 Me) 3 , Ga 2 (NMe 2 ) 6 , and water precursor system provided stoichiometric Er x Ga 22x O 3 films with carbon, hydrogen, nitrogen, and fluorine levels of 2.0-6.1, 5.0-10.3, ,0.3-0.7, and ¡0.1 atom percent, respectively, as determined by RBS and TOF-ERDA. The film growth rate was between 1.0 and 1.5 A ˚cycle 21 and varied as a function of the Er(C 5 H 4 Me) 3 to Ga 2 (NMe 2 ) 6 pulse ratio. The effective permittivity of representative samples was between 9.2 and 10.4. The as-deposited films of both precursor systems were amorphous, but crystallized either to Er 3 Ga 5 O 12 or to a mixture of b-Ga 2 O 3 and Er 3 Ga 5 O 12 upon annealing between 900 and 1000 uC under a nitrogen atmosphere. Atomic force microscopy showed root mean square surface roughnesses of ,1.0 nm for typical films regardless of precursor system or film composition.
