Atomic layer deposition of nickel and nickel germanide for next generation 3D devices

Abstract

Improvements in device performance in the memory and non-memory fields have resulted in innovations in device structure and materials. Structural innovation is a change in device structure in three dimensions. This change has made the atomic layer deposition process with ideal film uniformity even in complex struc-tures more important. At the same time, germanium is in the spotlight as a next-generation semiconductor material with high charge mobility and process compatibility, and has become the center of next-generation device technology by being mixed with the existing silicon process. In this study, we developed and applied nickel process through atomic layer deposition process to gate element and source / drain which are two ele-ments of device and evaluated its characteristics. In particular, Ni deposited through atomic layer deposition was applied as a metal for work function of the gate structure. The stability evaluation of the work function includes not only thermal stability but also changes when the work function is mixed with other metals and furthermore roll-off characteristics. All eval-uations were performed on hafnium oxide with high dielectric constant used in actual production, showing that ALD-Ni has excellent electrical properties. In addition, ALD-NiGe was obtained by reacting nickel deposited by atomic layer deposition and germani-um, a next-generation semiconductor material, for application to a source / drain. When the ALD-Ni and Ge substrates reacted, it was confirmed that impurities, which are fatal disadvantages of the chemical vapor deposition method, were diffused out. From this, a process was developed in which impurities are naturally removed without additional processes. From this, excellent source / drain characteristics could be evaluated and the contact resistivity characteristics were further improved by optimizing various dopant implant pro-cesses. Next-generation semiconductor materials will be applied to complex three-dimensional structures, the structures of next-generation devices. Therefore, the overall semiconductor device process and characteristic evaluation using the atomic layer deposition method in this study is considered to have high application val-ue for next-generation silicon and germanium devices with several nano-nodes.