LOW-FREQUENCY NEGATIVE CAPACITANCE BEHAVIOR OF MOLECULAR-BEAM EPITAXIAL GAAS N-LOW TEMPERATURE-I-P STRUCTURE WITH LOW-TEMPERATURE LAYER GROWN AT A LOW-TEMPERATURE

The GaAs sample under study is a n-low temperature-i-p structure grown by molecular beam epitaxy with a low-temperature (LT) layer grown at 300 degrees C and annealed at 620 degrees C for 1 h. Admittance measur ements on this sample reveal a negative capacitance at low frequency. This work analyzes the origin of the negative capacitance and its corr esponding frequency-dependent conductance by combining two current com ponents: charging-discharging current and the inertial conducting curr ent. Analysis results indicate that the activation energies and time c onstants of both current components closely resemble each other and sh ould correspond to the same trap. Based on the results presented herei n, we can conclude that the negative capacitance at low frequency prov ides evidence of a generation-recombination center with an activation energy of 0.77 eV in the LT layer. (C) 1998 American Institute of Phys ics.