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

详细信息    查看全文

• 作者：R. Ritzenthaler^a ; ^{romain.ritzenthaler@imec.be} ; T. Schram^a ; E. Bury^a ; ^c ; A. Spessot^b ; C. Caillat^b ; V. Srividya^b ; F. Sebaai^a ; J. Mitard^a ; L.-Å ; . Ragnarsson^a ; G. Groeseneken^a ; ^c ; N. Horiguchi^a ; P. Fazan^b ; A. Thean^a
• 关键词：DRAM periphery transistors ; RMG (Replacement Metal Gate) ; Work Function Engineering
• 刊名：Solid-State Electronics
• 出版年：2013
• 出版时间：June, 2013
• 年：2013
• 卷：84
• 期：Complete
• 页码：22-27
• 全文大小：2071 K

文摘

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/TaO_X/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.