The formation of ohmic Au/Mo/Ti contacts to epitaxial p-type diamond films is studied. The effect of annealing on the electrical and structural properties of contacts has been investigated. It was shown that during rapid thermal annealing, the outer layer of gold protects the contact system from oxidation up to a temperature of 850°C, unlike the simplified Au/Ti system, which is more common in modern works. In Au/Ti structures without a Mo layer after high-temperature annealing, effective diffusion of titanium into the gold layer occurs, which reduces its protective properties and accelerates the diffusion of oxygen to the boundary with the diamond. Oxidation of the Ti/C contact region blocks the formation of a conductive layer of titanium carbide with high adhesion at the border with diamond. The role of various factors in reducing the contact resistance is compared: annealing for the formation of titanium carbide, heavy doping of diamond with boron atoms, and crystalline perfection of epitaxial diamond substrates. For doped epitaxial films grown on single-sector quality substrates, non-annealed ohmic contacts with a record contact resistance of 4•10<-7> Ω•cm<2> were obtained.

Приведены результаты анализа атомного состава, уровня легирования и подвижности дырок в эпитак-сиальных слоях CVD (chemical vapor deposition) алмаза при легировании бором. Показаны возможности однородного легирования бором в диапазоне от 5 · 10 17 до ∼ 10 20 ат/см 3 и δ-легирования с поверхностной концентрацией (0.3 − 5) · 10 13 ат/см 2 . Определены режимы прецизионного ионного травления структур, сформированы барьерные и омические контакты к слоям.

Various methods of the formation of ohmic contacts to CVD diamond epitaxial structures with boron doped delta layers (δ-layers) are investigated. In the first approach, an additional thin, heavily doped layer was formed on the surface of the diamond film, to which the ohmic contact was formed. Then, the surface p+-layer between the contact pads was etched out, so the current flow in the structure occurred only through the buried δ-layer. In the second approach, doped diamond was selectively grown in contact windows under the mask of metal after preliminary etching the undoped diamond layer (cap) to the δ-layer. In this case, the heavily doped p+-layer will form a contact to the δ-layer. These approaches are differs by conditions of applicability, the complexity of manufacturing technology, the value of contact resistance. So they can be used to solve tasks in which different quality of contacts is required, such as the formation of transistor structures or test cells for measuring electrophysical characteristics.