15:45 〜 16:00
▲ [6p-A412-10] Growth and Characterization of Conductive Diamond Multilayers for Schottky Diodes
キーワード：diamond, conductive multilayer, Schottky diode
Recent progresses in diamond Schottky-barrier diodes (SBD) aimed to increase breakdown voltage and to minimize serial resistance. Therefore, serial resistance has been reduced by working on diode structures containing heavily boron-doped (p+) layers or conductive (p-type) substrates. However, highest breakdown voltages are still obtained on resistive conventional SBDs structures, based on insulating substrate without a p+-layer. We suppose that crystalline defects located inside p+-layer and at its interfaces initiate dislocations, which propagate throughout SBDs, and worsen breakdown voltage ability.
In this study, we fabricated highly crystalline conductive diamond multilayers by alternating thin boron-doped films with [B] ~ 1020 cm−3 (p+) and [B] ~ 1018 cm−3 (p–). These p+p– multilayers were used to build the conductive pathway of SBDs. Different B/C gas ratios have been employed to determine the effect of boron doping level on the crystallinity. Despite the variation of B/C gas ratios, doping levels in p+-layers remained unchanged. Boron incorporation saturated near the metal-semiconductor transition (~ 3×1020 cm−3). We made the hypothesis that incorporation saturation is correlated to a low density of dislocations in the layer. Therefore, we assume to increase charge carrier density in p+p– multilayers, while maintaining dislocation density low. That property of p+p– multilayer in SBDs has been appraised from reverse blocking voltage and forward current with respect to our previous results obtained on conventional SBDs.
In this study, we fabricated highly crystalline conductive diamond multilayers by alternating thin boron-doped films with [B] ~ 1020 cm−3 (p+) and [B] ~ 1018 cm−3 (p–). These p+p– multilayers were used to build the conductive pathway of SBDs. Different B/C gas ratios have been employed to determine the effect of boron doping level on the crystallinity. Despite the variation of B/C gas ratios, doping levels in p+-layers remained unchanged. Boron incorporation saturated near the metal-semiconductor transition (~ 3×1020 cm−3). We made the hypothesis that incorporation saturation is correlated to a low density of dislocations in the layer. Therefore, we assume to increase charge carrier density in p+p– multilayers, while maintaining dislocation density low. That property of p+p– multilayer in SBDs has been appraised from reverse blocking voltage and forward current with respect to our previous results obtained on conventional SBDs.