Title :
Positive temperature coefficient of impact ionization in strained-Si
Author :
Waldron, Niamh S. ; Pitera, Arthur J. ; Lee, Minjoo L. ; Fitzgerald, Eugene A. ; Alamo, Jesús A del
Author_Institution :
Massachusetts Inst. of Technol., Cambridge, MA, USA
fDate :
7/1/2005 12:00:00 AM
Abstract :
We have experimentally studied impact ionization (II) in the strained-Si layer of a strained-Si/SiGe heterostructure. Our key finding is that the impact ionization multiplication coefficient has a positive temperature coefficient which is opposite to that of bulk Si. Furthermore, the temperature dependence of the multiplication coefficient has been found to be exponential in nature. Our experimental work shows that the combination of a strong and positive temperature dependence of the II coefficient and the significant self-heating that this structure suffers from results in an overall impact ionization rate that is more than an order of magnitude higher than that of reference Si devices operating under identical bias conditions.
Keywords :
CMOS integrated circuits; Ge-Si alloys; elemental semiconductors; impact ionisation; semiconductor heterojunctions; silicon; Si-SiGe; bias conditions; germanium; impact ionization rate; multiplication coefficient; positive temperature coefficient; reference Si devices; self-heating; silicon; strained-Si layer; strained-Si/SiGe heterostructure; temperature dependence; CMOS technology; Germanium silicon alloys; Impact ionization; Radio frequency; Rapid thermal processing; Resistors; Silicon germanium; Temperature dependence; Testing; Thermal conductivity; Impact ionization; self-heating; strained-Si;
Journal_Title :
Electron Devices, IEEE Transactions on
DOI :
10.1109/TED.2005.850620
