Title :
Thermal stability of HfxTayN metal gate electrodes for advanced MOS devices
Author :
Cheng, Chin-Lung ; Chang-Liao, Kuei-Shu ; Wang, Tzu-Chen ; Wang, Tien-Ko ; Wang, Howard ChihHao
Author_Institution :
Inst. of Mech. & Electro-Mech. Eng., Nat. Formosa Univ., Yunlin, Taiwan
fDate :
3/1/2006 12:00:00 AM
Abstract :
In this letter, the composition effects of hafnium (Hf) and tantalum (Ta) in HfxTayN metal gate on the thermal stability of MOS devices were investigated. The work function of the HfxTayN metal gate can reach a value of ∼4.6 eV (midgap of silicon) by suitably adjusting the Hf and Ta compositions. In addition, with a small amount of Hf incorporated into a TaN metal gate, excellent thermal stability of electrical properties, including the work function, the equivalent oxide thickness, interface trap density and defect generation rate characteristics, can be achieved after a post-metal anneal up to 950°C for 45 s. Experimental results indicate that Ta-rich HfxTayN is a promising metal gate for advanced MOS devices.
Keywords :
MIS devices; MOS capacitors; hafnium compounds; rapid thermal annealing; silicon compounds; tantalum compounds; thermal stability; work function; 45 s; HfTaN; MOS devices; annealing; defect generation rate; electrical properties; equivalent oxide thickness; interface trap density; metal gate electrodes; thermal stability; work function; Character generation; Electrodes; Hafnium; MOS devices; Rapid thermal annealing; Silicon; Spectroscopy; Thermal stability; Transistors; Voltage; metal gate; thermal stability; work function;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2005.863563
