Structural and electrical properties of CVD diamond films doped by N+ implantation

Chemical vapor deposited (CVD) diamond films (DF) were prepared on P-type < 100 > oriented Si substrates. The films were implanted with 140 keV N+ to doses of 5 x 10(14) similar to 1 x 10(16)cm(-2), respectively. Under the im plantation, the DF becomes more and more disordered with each increasing do se. Scanning electronic microscopy (SEM) and Raman measurements reflect the amorphization process. Combining the electrical resistance measurements, i t is clear that polycrystalline DF has a higher threshold dose of amorphiza tion than that for bulk ones. The damages induced by implantation can be pa rtially removed by annealing when the dose is below the critical value. Lar ger doses of implantation produce amorphous carbon which can transform into micro-polycrystalline graphite during annealing. Thus, the conductivity is increased dramatically. However, for smaller dose N+ implanted samples, wh ile annealing was performed, the samples become comparable conductive for t he activation of N dopants. (C) 2000 Elsevier Science S.A. All rights reser ved.