Charge deep-level transient spectroscopy of Al/intrinsic diamond/p(+)-Si Schottky diodes

Charge deep-level transient spectroscopy (Q-DLTS) and the feedback charge c apacitance method (FCM) were applied to Al/intrinsic diamond/p-Si diodes, u sing the top Al electrode as a Schottky gate. The Q-DLTS data recorded over the temperature range of 90-450 K could be split into two components: (i) a peak of the signal due to a discrete energy level, the hole emission of w hich is thermally activated by DeltaE = 0.29 +/- 0.02 eV; (ii) a broad spec trum of relaxation times manifesting itself as a signal that increases cont inuously on heating the diodes toward the ultimate temperature. To exclude any effects caused by the silicon back contact (Al), Q-DLTS spectra taken a t different polarities of the filling pulse were compared. The related FCM capacitance-voltage measurements at the uppermost temperature revealed no c hanges in the capacitance with bias if sampling the time domain capacitance in the microsecond region. Over a longer timescale an excess capacitance w as detected as expected on the basis of the complementary Q-DLTS data. Taki ng into account the absence of any capacitance changes at lower temperature s and/or short observation times (excitation), it is concluded that the def ects reside in the polycrystalline diamond layer rather than at the diamond /silicon interface.