Diamond electronic devices fabricated using heavily doped hopping p+and n+layers

Diamond diodes with extremely low on-resistance are introduced and discussed. Heavily boron-doped p+-type and phosphorus-doped n+-type diamond films with hopping conduction at room temperature are utilized. These diamond films have a unique property, that is, their resistivity decreases drastically even at a high impurity concentration of ∼1020 cm−3 without degrading the crystallinity. This unique property is applied to two kinds of diamond diodes. One is a p+–i–n+ junction diode. The other is a Schottky-pn diode consisting of the combination of the p+–n and n-type Schottky junctions. Current–voltage and capacitance–voltage characteristics are evaluated for both diodes. Switching characteristics are also evaluated for Schottky-pn diodes. The results show a low on-resistance on the order of mΩ cm2 and fast switching on the ns order. These results indicate that the low-loss diamond diodes can be realized by using the hopping p+- and n+-type layers.