Fabrication of diamond (including diamond-like carbon: DLC) films as electronic materials requires several conditions. They are: (1) low-temperature fabrication (or deposition on several substrates) below 300 degrees C, (2) wide-area film deposition onto wide substrates of several square inches, like Si wafer, (3) reproducible deposition of well-defined film quality, and (4) others. In these respects, we have initiated, in the author's laboratories at Osaka University and Kochi University of Technology, a quite new approach to satisfy the above requirements by using microwave plasma CVD under a magnetic field to be called as "magneto-active plasma CVD." The films thus fabricated, combined with our special nano-seeding method, have been used as electron emitter with high efficiency for a 3-year Japanese national project "Development of Ultra Thin Flat Panel Display'' that started in 1997 with the author being appointed as the project leader.