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.

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.