Title :
Plasma-Induced Damage in High-
/Metal Gate Stack Dry Etch
Author :
Hussain, Muhammad Mustafa ; Song, Seung-Chul ; Barnett, Joel ; Kang, Chang Yong ; Gebara, Gabe ; Sassman, Barry ; Moumen, Naim
Author_Institution :
SEMATECH, Austin, TX
Abstract :
Plasma-based dry etch is used as the industry standard gate etch in conventional CMOS fabrication flow. However, past studies indicate that plasma-induced dry etch may impact device performance. The current research trend toward replacing conventional silicon dioxide and polysilicon gate stacks with high-k/metal gate stacks introduces a new challenge: development of new dry etch processes for critical new metals and their alloys. In this letter, a comparative study in the context of device performance has been conducted to compare dry etch versus wet etch for gate stack etch of hafnium oxide/tantalum silicon nitride gate stack. It has been found that the dry-etched gate stack exhibit significantly more gate leakage current and poorer uniformity in threshold-voltage distribution
Keywords :
MOSFET; etching; leakage currents; plasma materials processing; CMOS fabrication; gate leakage current; gate-induced drain leakage; hafnium oxide/tantalum silicon nitride gate stack; high-k/metal gate stack dry etch; plasma-based dry etch; plasma-induced damage; plasma-induced dry etch; polysilicon gate stacks; silicon dioxide; threshold-voltage distribution; wet etch; Dry etching; Fabrication; High K dielectric materials; High-K gate dielectrics; Plasma applications; Plasma devices; Silicon alloys; Silicon compounds; Textile industry; Wet etching; Gate-induced drain leakage (GIDL); high-$k$/metal gate; plasma dry etch; threshold-voltage; wet etch;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2006.886327