Some investigations on HF-CVD diamond using scanning tunneling microscopy

Diamond films grown by the hot filament chemical vapor deposition technique (HF-CVD) on tungsten carbide tool are characterized by scanniag electron microscopy (SEM), Raman spectroscopy, low angle X-ray diffraction and scanning tunneling microscopy (STM). The most striking result of the present work is the fact that diamond films could be imaged easily and reproducibly using STM. On the micron scale STM images depict “roof shaped” morphology corresponding to the edges of cubo-octahedral diamond crystals in agreement with SEM results. Higher magnification STM images indicate that the edges are composed of alternate flat-rough, flat-ridged or only flat planes. The planes were full of steps and screw dislocations. I-S measurement on tunnel junction supports tunneling as a dominant imaging mechanism whereas I-V measurement indicate that there exists a considerable barrier distortion and/or presence of impurity states in the diamond band gap.