Impact of cryogenic temperature operation on static and low frequency noise behaviors of FD UTBOX nMOSFETs

Abstract

Unusual peaks in the transconductance gm(VGS) characteristics of n-channel UTBOX devices have been evidenced at 10 K and 77 K operation for an applied front gate voltage around 1.1 V while the back gate is grounded. The origin of this behavior was also addressed using additional low frequency noise (LFN) measurements. It is believed that the unusual peak may be related to a tunneling effect through dopants diffused from source/drain extensions in the channel. Low frequency noise spectroscopy around 77 K confirms the presence of boron in the Si film. Back gate biased in accumulation mode at 77 K operation evidenced an additional transconductance peak behavior which may be attributed to the linear kink effect.