Sb. Felch et al., CHARACTERIZATION OF ULTRA-SHALLOW P(-N JUNCTIONS FORMED BY PLASMA DOPING WITH BF3 AND N-2 PLASMAS()), Materials chemistry and physics, 54(1-3), 1998, pp. 37-43
Plasma doping (PLAD) is a promising alternative to conventional ion im
plantation for the formation of ultra-shallow p(+)-n junctions. In the
PLAD process, a silicon wafer is placed directly in a plasma containi
ng the desired dopant ions and then pulse-biased to a negative potenti
al to accelerate positive dopant ions into the silicon surface. Most o
f Varian's work to date has used BF, source gas and wafer biases of -0
.5 to -5 kV to implant boron into 150 and 200 mm wafers. Data will be
presented showing successful formation of ultra-shallow junctions, goo
d sheet resistance uniformity and repeatability, and excellent structu
ral quality of the silicon after rapid annealing. Very good device cha
racteristics obtained from deep sub-half micron MOSFETs fabricated usi
ng PLAD will also be shown. Finally, the combination of PLAD with an N
-2 plasma followed by ultra-low energy B+ implantation to produce ultr
a-shallow junctions with low sheet resistances will be discussed. (C)
1998 Elsevier Science S.A. All rights reserved.