Title :
Effects of annealing on charge in HfO/sub 2/ gate stacks
Author :
Zhang, Z. ; Li, M. ; Campbell, S.A.
Author_Institution :
Dept. of Electr. & Comput. Eng., Univ. of Minnesota, Minneapolis, MN, USA
Abstract :
This letter presents a systematic investigation of charge in HfO/sub 2/ gate stacks. Assuming that the majority of charge is associated with the stack interfaces, it is found that the charge at the HfO/sub 2//interfacial layer (IL) interface is negative while the charge at the Si/IL interface is positive. In general, the calculated charge densities at both interfaces are of order 10/sup 12/ cm/sup -2/. A forming gas anneal (FGA) reduces the interface charge greatly at both interfaces. However, the FGA temperature does not have much effect on the charge density. The effects of post deposition anneal at various temperatures and under various atmospheres are also studied. Its found that a high temperature dilute oxidizing atmosphere anneal reduces the charge at both interfaces.
Keywords :
annealing; electrodes; forming processes; hafnium compounds; interface states; silicon; work function; HfO/sub 2/; HfO/sub 2/ gate stacks; Si; Si-IL interface; annealing effects; dilute oxidizing atmosphere; forming gas anneal; interfacial layer interface; metal gate electrode; stack interfaces; work function; Annealing; Atmosphere; Chemical vapor deposition; Chromium; Dielectrics and electrical insulation; Electrodes; Hafnium oxide; Temperature; Voltage; Annealing; charge; gate dielectric; high-; metal gate electrode; work function;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2004.840016
