Abstract: There are disclosed impedance matching networks and technique for impedance matching to microwave power transistors. Distributed capacitor inductor networks are used so as to provide a high degree of control and accuracy, especially in terms of inductance values, in comparison to existing lumped capacitor arrangements. The use of bond wires is reduced, with inductance being provided primarily by microstrip transmission lines on the capacitors.

Abstract: Some embodiments of the present invention provided an impedance-transforming arrangement comprising a plurality of microwave power transistors 41, and at least one intermediate impedance-transforming or matching device 30. The matching device comprises a plurality of elongate microwave transmission lines 31 provided in or on at least one dielectric substrate 32, extending across or through the dielectric substrate. The microwave transmission lines are coupled at one end to the gate pads 47 of the transistor and at the input ends to a signal input terminal for the transmission line. The transmission lines are substantially directly coupled to one another by means of resistive elements 35 providing a current flow path between the two transmission lines in order to reduce any residual tendency to instability caused by manufacturing variations or misalignment in the assembly process.

Abstract: There are disclosed impedance matching networks and technique for impedance matching to microwave power transistors. Distributed capacitor inductor networks are used so as to provide a high degree of control and accuracy, especially in terms of inductance values, in comparison to existing lumped capacitor arrangements. The use of bond wires is reduced, with inductance being provided primarily by microstrip transmission lines on the capacitors.

Abstract: Electronic field effect devices, and methods of manufacture of these electronic field effect devices are disclosed. In particular, there is disclosed an electronic field effect device which has improved electrical properties due to the formation of a highly mobile two-dimensional charge-carrier gas in a simple structure formed from diamond in combination with polar materials.

Abstract: Electronic field effect devices, and methods of manufacture of these electronic field effect devices are disclosed. In particular, there is disclosed an electronic field effect device which has improved electrical properties due to the formation of a highly mobile two-dimensional charge-carrier gas in a simple structure formed from diamond in combination with polar materials.

Abstract: Electronic field effect devices, and methods of manufacture of these electronic field effect devices are disclosed. In particular, there is disclosed an electronic field effect device which has improved electrical properties due to the formation of a highly mobile two-dimensional charge-carrier gas in a simple structure formed from diamond in combination with polar materials.

Abstract: Electronic field effect devices, and methods of manufacture of these electronic field effect devices are disclosed. In particular, there is disclosed an electronic field effect device which has improved electrical properties due to the formation of a highly mobile two-dimensional charge-carrier gas in a simple structure formed from diamond in combination with polar materials.

Abstract: A method of manufacturing a transistor, typically a MESFET, includes providing a substrate including single crystal diamond material having a growth surface on which further layers of diamond material can be deposited. The substrate is preferably formed by a CVD process and has high purity. The growth surface has a root-mean-square roughness of 3 nm or less, or is free of steps or protrusions larger than 3 nm. Further diamond layers are deposited on the growth surface to define the active regions of the transistor. An optional n+ shielding layer can be formed in or on the substrate, following which an additional layer of high purity diamond is deposited. A layer of intrinsic diamond may be formed directly on the upper surface of the high purity layer, followed by a boron doped (“delta doped”) layer. A trench is formed in the delta doped layer to define a gate region.