Modeling and analysis of the admittance characteristics of n~+ metal-oxide-semiconductor capacitors with oxide and interface states - Gd_(0.25)Ga_(0.15)O_(0.6)/Ga_2O_3 on In_(0.53)Ga_(0.47)As

摘要

The 300-K admittance characteristics of n~+ In_(0.53)Ga_(0.47)As MOS capacitors with a dielectric stack of Gd_(0.25)Ga_(0.15)O_(0.6)/Ga_2O_3 in as-grown condition are examined in detail and compared to an oxide trap model that we previously introduced. The model explains many of the observed features not contained in the interface state model. By fitting the model to experimental data, we extract a distribution of defect states in space and energy within the oxide and at the oxide/semiconductor interface separately. Oxide states are the dominant defects over a wide range of energy. The defect state densities are not subject to the usual resolution limits of conventional analyses. Using this approach, it is possible to characterize relatively rapidly a wide range of energies at a single temperature without the need for reaching the low or high limits of frequency. The implications for the conventional interface state density (D_(it)) extraction techniques are explored. It is shown how oxide states can affect the extraction of sample parameters, particularly the insulator capacitance, and can result in a range of extracted D_(it) values. We believe these contribute to the wide range of D_(it) reported in the literature from similar admittance characteristics of a number of oxides on In_(0.53)Ga_(0.47)As.