6. Conclusion

The technical field of ALD reactors has evolved considerably over the last few decades. A variety of mature and reliable equipment types are now available. The most appropriate choice of equipment depends very much on the particular application. A large number of performance indicators exist, such as substrate size, choice of available precursors, minimum cycle time, physico-chemical properties of deposited layers, process uniformity and stability, microcontamination, equipment reliability and cost. The relative importance given to these metrics in equipment selection depends on the final application.

There is a continuing trend towards innovation in this field, both in terms of reactor architectures, subsystems and components, fuelled by the growing number of applications. The main areas of development are :

• lower...