SOME INVESTIGATIONS ON HF-CVD DIAMOND USING SCANNING-TUNNELING-MICROSCOPY

Diamond films grown by the hot filament chemical vapor deposition tech nique (HF-CVD) on tungsten carbide tool are characterized by scanning electron microscopy (SEM), Raman spectroscopy, low angle X-ray diffrac tion and scanning tunneling microscopy (STM). The most striking result of the present work is the fact that diamond films could be imaged ea sily and reproducibly using STM. On the micron scale STM images depict ''roof shaped'' morphology corresponding to the edges of cube-octahed ral diamond crystals in agreement with SEM results. Higher magnificati on STM images indicate that the edges are composed of alternate flat-r ough, flat-ridged or only flat planes. The planes were full of steps a nd screw dislocations. I-S measurement on tunnel junction supports tun neling as a dominant imaging mechanism whereas I-V measurement indicat e that there exists a considerable barrier distortion and/or presence of impurity states in the diamond band gap.