Peculiarity of Depletion Region in Diamond pn-Junction

Abstract

Ionized dopant and carrier profiles in the pn-junction of diamond with a deep phosphorus donor and a boron acceptor are theoretically analyzed by simply solving a one-dimensional Poisson equation. The width of the depletion layer is around two times larger than that of the space-charge layer since there exists a transition region at the depletion layer edge. The difference between these widths is reduced with increasing temperature. It is predicted that the static saturation property of a bipolar pnp-junction transistor is affected by the large width of the depletion layer. A base donor density higher than high-1018 cm-3 is required for an acceptor density of 1×1018 cm-3 in the collector to obtain an Early voltage larger than 100 V. Similarly, a punch-through voltage is extremely reduced by the deep dopant effect. However, the deep dopant effect is weakened with increasing temperature.