Low-power DRAM-compatible Replacement Gate High-k/Metal Gate Stacks

作者：Ritzenthaler R^*; Schram T; Bury E; Spessot A; Caillat C; Srividya V; Sebaai F; Mitard J; Ragnarsson L A; Groeseneken G; Horiguchi N; Fazan P; Thean A

来源：Solid-State Electronics, 2013, 84: 22-27.

DOI：10.1016/j.sse.2013.02.026

• DRAM periphery transistors
• RMG (Replacement Metal Gate)
• Work Function Engineering

In this work, the possibility of integration of High-k/Metal Gate (HKMG), Replacement Metal Gate (RMG) gate stacks for low power DRAM compatible transistors is studied. First, it is shown that RMG gate stacks used for Logic applications need to be seriously reconsidered, because of the additional anneal(s) needed in a DRAM process. New solutions are therefore developed. A PMOS stack HfO2/TiN with TiN deposited in three times combined with Work Function metal oxidations is demonstrated, featuring a very good Work Function of 4.95 eV. On the other hand, the NMOS side is shown to be a thornier problem to solve: a new solution based on the use of oxidized Ta as a diffusion barrier is proposed,and a HfO2/TiN/TaOx/TiAl/TiN/TiN gate stack featuring an aggressive Work Function.of 4.35 eV (allowing a Work Function separation of 600 mV between NMOS and PMOS) is demonstrated. This work paves the way toward the integration of gate-last options for DRAM periphery transistors. 2013 Elsevier Ltd.

• 出版日期2013-6