Scattering noise of hot holes in space-charge-limited current flow in p-type Si

Abstract

Experimental data are presented for the spectral density of the scattering fluctuations of hot holes in space-charge-limited current flow in p-type Si. Measurements have been made in the temperature range 100–300 K for electric field strengths up to 106 V/m. To avoid excessive heating of the lattice, measurements were performed under pulsed bias conditions. The experimental curves are compared with those calculated for thermal carriers. At room temperature no hole heating effects are observed for electric field strengths up to 4.5×105 V/m. Above this limit hole heating sets in. A noise temperature Tn is defined which is a proper measure for departures from the thermal equilibrium carrier-velocity distribution. The field strength which marks the onset of hot-hole phenomena gradually decreases with decreasing lattice temperature T and reaches the value 1.5×103 V/m at 100 K. At this temperature noise temperatures of 3T are observed for fields up to 106 V/m. Evidence is put forward for the presence of a hole trapping energy level 0.3 eV above the valence band with hole capture cross section (2.0±1.0) ×10−19 m2.