The vertical-type metal-base organic transistors ( MBOT) are high-performance transistors which have a simple layered structure of organic/metal/organic layers. In this study, we investigated various structures for the collector layer to enhance current modulation and reduce operation voltage. The device having collector layers composed of perylene derivatives/bathocuproine(BCP)/C(60) and base electrode of LiF/Al showed very high current modulation of 165.1 A/cm(2) at 2 V of collector voltage and 1 V of base voltage. We found that the LiF layer and BCP layer contribute to current enhancement, and the C(60) layer contributes to suppression of leakage current, respectively.