M. Herden et al., Suppression of boron penetration through thin gate oxides by nitrogen implantation into the gate electrode of PMOS devices, MICROEL REL, 40(4-5), 2000, pp. 633-636
PMOS devices with different amounts of nitrogen implanted into the gate ele
ctrode before doping with BF2 implantation and implant anneal were manufact
ured, The thicknesses of the gate oxides grown in dry oxygen by RTP were 4.
1 down to 2.8 nm, The implant anneal was also performed by RTP. The influen
ce of the nitrogen on the penetration of boron ions through the ultra-thin
gate oxides into the channel region was investigated by electrical and SIMS
measurements. Boron was effectively prevented from diffusion by high nitro
gen concentrations at the polysilicon/ gate oxide interface without degradi
ng the reliability, In return, increased sheet resistivities and gate deple
tion have to be taken into account by high nitrogen concentrations within t
he polysilicon gate electrode, (C) 2000 Elsevier Science Ltd. All rights re
served.