Experimental studies of N+ implantation into CVD diamond thin films

The effects of N+ implantation under various conditions on CVD diamond films were analyzed with Raman spectroscopy, four-point probe method, X-ray diffraction (XRD), Rutherford backscattering spectroscopy (RBS), ultraviolet photoluminescence spectroscopy (UV-PL), Fourier transformation infrared absorption spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The results show that the N+ implantation doping without any graphitization has been successfully realized when 100 keV N+ ions at a dosage of 2 x 10(16) cm(-2) were implanted into diamond films at 550 degrees C. UV-PL spectra indicate that the implanted N+ ions formed an electrically inactive deep-level impurity in diamond films. So the sheet resistance of the sample after N+ implantation changed little. Carbon nitride containing C=N covalent bond has been successfully synthesized by 100 keV, 1.2 x 10(18) N/cm(2) N+ implantation into diamond films. Most of the implanted N+ ions formed C=N covalent bonds with C atoms. The others were free state nitrogen, which existed in the excessive nitrogen layers. C(1s) XPS studies show the existence of three different C(1s) bonding states, corresponding to graphite, i-carbon and the carbon of C=N covalent bonding state, respectively, which agrees well with the Raman results.