Full ALD Ta2O5-based stacks for resistive random access memory grown with in vacuo XPS monitoring

Abstract Ta 2 O 5 -based metal-insulator-metal stacks for resistive random access memory were grown by atomic layer deposition technique only with the emphasis on different top metal–oxide interface engineering. The impact of top TiN electrode growth and NH 3 treatment on dielectric chemical and electrical properties was discussed. In addition the TiN/Ta 2 O 5 /Al 2 O 3 /TiN stack with bilayer dielectric was grown and studied too. According to in vacuo XPS analysis at top interface both TiN/Ta 2 O 5 /TiN and TiN/Ta 2 O 5 (NH 3 -treated)/TiN stacks comprise the TaO x N y interlayer which is twice thicker in the case of stack with NH 3 treatment (∼1.3 nm) in comparison with untreated one (∼0.7 nm). In vacuo XPS analysis also showed that 2 nm Al 2 O 3 insert between Ta 2 O 5 and top TiN electrode allowed to completely block formation of TaO x N y interlayer at TiN/Ta 2 O 5 /Al 2 O 3 /TiN stack. As a result it was found that TiN/Ta 2 O 5 /TiN demonstrated gradual and rather slow (∼10 −3  s) character of resistive switching while the switching at stack with bilayer Ta 2 O 5 /Al 2 O 3 dielectric is much more abrupt, faster and it reveals more than one order of magnitude higher endurance.