PERGAMON Microelectronics Reliability38 (1998) 931-936
MICROELECTRONICS
RELIABILITY
Hot carrier degradation mechanisms in sub-micron p channel
MOSFETs: Impact on low frequency (l/f) noise behaviour
E. Sheehan, P.K. Hurley and A. Mathewson
National Microelectronics Research Centre, University College Cork,
Lee Maltings, Prospect Row, Cork, Ireland.
Abstract
In this work we present new results which illustrate the impact of hot carrier (HC) degradation
on the low frequency (I/f) noise behaviour of submicron p channel MOSFETs. Submicron p channel
MOSFETs were subjected to HC stress at a range of gate bias conditions, and the response of the low
frequency noise was recorded. The results obtained are in marked contrast to the reported influence of
HC stress on nMOSFETs 1/f noise, and indicate that the measurement of 1/f noise is a useful tool for
investigating HC induced aging effects in submicron p channel devices. The significance of these results
to the use of pMOSFETs in analog applications is briefly discussed.
© 1998 ElsevierScienceLtd. All rights reserved.
I. Introduction
Several previous studies have reported that hot
carrier (HC) degradation [1-4] and plasma charging
damage [5] have a significant impact on the low
frequency (l/f) noise behaviour of n channel
MOSFETs. The increase in the 1/f noise levels has
been attributed to a generation of slow states in the
gate oxide during the high field stress. Analysis has
identified the generated slow states to be located in
a narrow region (<50 nm) surrounding the drain of
the device [1,2]. Furthermore, the sensitivity of 1/f
noise to the Si-SiO2 interface properties has resulted
in the use of 1/f noise measurements as a monitor
for HC induced oxide degradation in n channel
devices.
0026-2714/98/$ - see front matter. © 1998 ElsevierScienceLtd. All rights reserved.
PII: S0026-2714(98)00143-7