Atomic layer chemical vapor deposition (ALCVD) of Hf and Zr silicate and aluminate high-k gate dielectric for next generation nano devices

Abstract

Among many deposition techniques, atomic layer deposition (ALD) is well suited for highly conformal and uniform ultrathin films with accurate thickness control over a large area. A number of ALD deposition processes have been used to grow mixed oxides like Hf or Zr silicate and aluminate thin films for high-k gate dielectrics needed in the next generation silicon transistors. Nano laminate mixing of each oxide by switching between two metal precursors with an oxidant like water can be used and film composition can be controlled by adjusting the number of each single oxide cycles. An alternating injection of metal alkoxides and chlorides without the injection of extra oxidants is another method. Single metal source, which contains both metal and Si (or Al), also can be adopted to form silicate or aluminate films. These processes will be overviewed in this article with our recent work on atomic layer deposition (ALD) of high-k gate dielectrics. It is important to select a proper set of precursors and each process should be evaluated and compared in terms of the reliability and film properties. In-situ diagnostic technique such as FT-IR is also helpful for the process development.