The growth of monocrystalline diamond films of electronic quality and large thickness (>few hundreds of microns) is an important issue in particular for high-power electronics. In this paper, we will describe the different key parameters necessary to reach this objective. First, we will examine the deposition process and establish that only microwave assisted diamond deposition plasma reactors can achieve the optimal growth conditions for the efficient generation of the precursor species to diamond growth. Next, we will consider the influence of the monocrystalline diamond substrate orientation and quality on the growth of the epitaxial layer, especially when the deposited material thickness exceeds 100 µm. The need to use a specific pre-treatment procedure of the substrate before the growth and its impact will also be discussed. Finally we will look at the growth conditions themselves and assess the influence of the process parameters, such as the substrate temperature, the methane concentration, the microwave power density and the eventual presence of nitrogen in the gas phase, on both the morphology and quality of the films on the one hand and the growth rate on the other hand. For this, we will introduce the concept of supersaturation and comment on its evolution as a function of the process parameters.

Diamond has been identified as a very promising material for X and ultraviolet sensing. In this Letter, a photoconductive device based on a freestanding homoepitaxial chemically vapor deposition (CVD) single-crystal diamond 500μm thick has been tested. Photoconductive measurements in coplanar and transverse configurations have been performed to characterize the device sensitivity in the 140–250 nm spectral range. Very high sensitivity values were achieved in both configurations. The sensitivity in the transverse configuration is at least 300 times higher than in the coplanar configuration.