An NIMS (National Institute for Materials Science) research group claims a first in having developed logic circuits equipped with diamond-based MOSFETs at two different operation modes.

The achievement reportedly is a first step toward the development of diamond integrated circuits operational under extreme environments, such as high temperature as well as exposure to (space) radiation and cosmic rays.

Diamond is a promising material to be used in the development of current switches and integrated circuits that are required to operate stably at high temperature, high frequency, and high power.

It had been difficult, however, to enable diamond-based MOSFETs to control the polarity of the threshold voltage, and to fabricate MOSFETs of two different modes – a depletion mode (D mode) and an enhancement mode (E mode) – on the same substrate. To solve this problem, the research group developed a threshold control technique that allowed them create hydrogenated diamond NOT and NOR logic circuits composed of D-mode and E-mode MOSFETs.

The MOSFETs are said to act as load and driver devices for the logic circuits, thus providing complementary transistor actions.