Solid-state diffusion and conventional ion implantation are not suitab
le for source and drain regions formation of polysilicon thin-film tra
nsistors on glass substrates. A 30 cm diameter large-area low-energy i
on shower implanter with RIPE ion source and double-grid extraction sy
stem was developed as a possible low-cost solution. The ion beam curre
nt density for hydrogen plasma was 100 muA/cm2 for 3 keV implant energ
y, 300 W RF power, 140 gauss magnetic field and 3 x 10(-4) mbar pressu
re. The uniformity of beam current density over the central 20 cm diam
eter was +/- 3.5%. Phosphorus implantation has been performed using a
15% PH3 in H-2 gas mixture. Implantation at 3 keV for 5 min. results i
n an integrated dose of 2.48 x 10(16) cm-2, with the concentration pea
k at a depth of 8.3 nm. Planar and mesa diodes fabricated on p-type si
licon substrates have yielded fine rectifier characteristics. The show
er implanter is thus suitable for TFTs source and drain region formati
on.