ELECTRICAL-PROPERTIES OF B-DOPED HOMOEPITAXIAL DIAMOND(001) FILM

Relationship between growth condition and quality of homoepitaxially g rown B-doped diamond (001) film has been studied using physical measur ements of defect density as a function of doping concentration. In par ticular, electrical properties of the homoepitaxial diamond film were characterized using measurements of conductivity, carrier concentratio n and mobility. The highest mobility is found to be about 1000 cm(2) V -1 s(-1) at 293 K, indicating that the quality of the CVD diamond film is further improved through optimizing the growth condition. The dens ity of the compensation donor was determined from the temperature-depe ndent hole concentration. The lowest donor density is found to be 8.4 x 10(15) cm(-3) in the present work. This is an order of magnitude gre ater than the lowest value measured in natural IIb diamond. Furthermor e, it is also found that the donor density increases with increasing d oping concentration during the growth. On the other hand, the mobility decreases rapidly with increasing doping concentration. From these re sults, we speculate that the compensation donor is an origin of an add itional scattering center in diamond, and excessive B-doping makes the quality of the CVD diamond worse. (C) 1997 Elsevier Science S.A.