Title :
Electron mobility in ULSI MOSFETs: effect of interface traps and oxide nitridation
Author :
Perron, L. ; Lacaita, A.L. ; Pacelli, A. ; Bez, R.
Author_Institution :
CNR, Politecnico di Milano, Italy
fDate :
5/1/1997 12:00:00 AM
Abstract :
We provide a comprehensive set of electron mobility measurements at 300 K and 77 K on standard and N/sub 2/O-nitrided MOSFETs, with channel doping in the range 3.8/spl times/10/sup 17/-1.25/spl times/10/sup 18/ cm/sup -3/. In such heavily-doped devices, the Fermi level always lies very close to the conduction band edge, where interface traps reach the highest density and the shortest lifetimes. We show that these traps contribute to the gate-channel capacitance, leading to a systematic overestimate of the channel charge. This effect has the largest impact precisely in the roll-off region of the mobility curves, which has been the subject of recent theoretical investigations.
Keywords :
Fermi level; MOS integrated circuits; MOSFET; ULSI; capacitance; electron mobility; electron traps; heavily doped semiconductors; hole traps; integrated circuit reliability; interface states; nitridation; semiconductor device reliability; 77 to 300 K; Fermi level; N/sub 2/O; N/sub 2/O-nitrided MOSFET; ULSI MOSFET; channel charge; channel doping; conduction band edge; electron mobility measurements; gate-channel capacitance; heavily-doped devices; interface traps; mobility curves; oxide nitridation; rolloff region; Capacitance; Degradation; Doping; Electrical resistance measurement; Electron mobility; Electron traps; Furnaces; MOSFET circuits; Rapid thermal processing; Ultra large scale integration;
Journal_Title :
Electron Device Letters, IEEE
