Abstract :
Rectifying contacts to polycrystalline diamond (PCD) can be improved signi®cantly by using a metal/undoped PCD/p-type
doped PCD structure. In this paper, a model for the reverse current of a metal/undoped PCD/p-type doped PCD junction diode
is proposed. In this model, the undoped PCD is treated as a slightly doped p-type semiconductor due to the existence of the
deep level defects of acceptor-states. The electric ®eld, which is needed to calculate the reverse current, is obtained by
considering the p-type doped PCD layer and the undoped PCD layer as a high±low junction. The reverse current is therefore,
modeled as the transport of holes through the undoped PCD layer based on the Poole±Frenkel effect. The simulated reverse
current is compared with experimental results and a good agreement between the simulated and experimental results is
achieved. # 2001 Elsevier Science B.V. All rights reserved.
