R. Padma

Electrical Properties of Rapidly Annealed Ir and Ir/Au Schottky Contacts on n-Type InGaN

The effect of annealing temperature on electrical characteristics of iridium (Ir) and iridium/gold (Ir/Au) Schottky contacts to n-type InGaN have been investigated by means of current-voltage (I-V) and capacitance-voltage (C-V) techniques. It is observed that the barrier height of Ir/n-InGaN and Au/Ir/n-InGaN Schottky diodes increases after annealing at 300∘C for 1 min in N2 ambient compared to the as-deposited. However, the barrier heights are found to be decreased somewhat after annealing at 500∘C for the both Ir and Ir/Au Schottky contacts. From the above observations, it is clear that the optimum annealing temperature for both Ir and Ir/Au Schottky contacts is 300∘C. Moreover, the barrier height (𝜙𝑏), ideality factor (n) and series resistance (𝑅𝑆) are determined using Cheung’s and Norde methods. Besides, the energy distribution of interface state densities are determined from the forward bias I-V characteristics by taking into account the bias dependence of the effective barrier height. Based on the above results, it is clear that both Ir and Ir/Au Schottky contacts exhibit a kind of thermal stability during annealing.

Electrical parameters and current conduction mechanism in Cr/Au/n-InP Schottky structure at different annealing temperatures

Cr/Au/n-InP Schottky structures are fabricated and their electrical characteristics are investigated at different annealing temperatures. As-deposited Cr/Au/n-InP Schottky diode exhibits a barrier height of 0.51 eV (I-V) and 0.64 eV (C-V), which increases to 0.63 eV (I-V) and 0.75 eV (C-V) after annealing at 100 °C. A maximum barrier height of 0.71 eV (I-V) and 0.81 eV (C-V) is achieved for the Cr/Au Schottky contacts after annealing at 200 °C. Further, it is observed that the Schottky barrier height slightly decreases upon annealing at temperature of 300 °C and the obtained values are 0.58 eV (I-V), 0.69 eV (C-V). The reverse-bias leakage current mechanism of Cr/Au/n-InP Schottky barrier diode is investigated. Investigations reveal that the Schottky emission is the dominant mechanism and the Poole-Frenkel emission occurs only in the high voltage region.

Electrical properties and the determination of interface state density from I – V , C – f and G – f measurements in Ir/Ru/ n -InGaN Schottky barrier diode

The electrical properties of the Ir/Ru Schottky contacts on n-InGaN have been investigated by current-voltage (I–V), capacitance-voltage (C–V), capacitance-frequency (C–f) and conductance-frequency (G–f) measurements. The obtained mean barrier height and ideality factor from I–V are 0.61 eV and 1.89. The built-in potential, doping concentration and barrier height values are also estimated from the C–V measurements and the corresponding values are 0.62 V, 1.20 × 1017 cm–3 and 0.79 eV, respectively. The interface state density (NSS) obtained from forward bias I–V characteristics by considering the series resistance (RS) values are lower without considering the series resistance (RS). Furthermore, the interface state density (NSS) and relaxation time (τ) are also calculated from the experimental C–f and G–f measurements. The NSS values obtained from the I–V characteristics are almost three orders higher than the NSS values obtained from the C–f and G–f measurements. The experimental results depict that NSS and τ are decreased with bias voltage. The frequency dependence of the series resistance (RS) is attributed to the particular distribution density of interface states.

Determination of the characteristic parameters of Au/PVDF/n-InP Schottky structure from current-voltage and capacitance-voltage measurements

The effect of polyvinylidene fluoride (PVDF) polymer interlayer on the rectifying junction parameters of Au/n-InP Schottky diode have been investigated using current-voltage (I-V) and capacitance-voltage (C-V) measurements at room temperature. Experimental results show that Au/PVDF/n-InP structure exhibits a good rectifying behavior. The calculated barrier heights (BHs) are 0.73 eV (I-V), 0.88 eV (C-V) for Au/PVDF/n-InP Schottky diode, respectively. The values of the barrier height, ideality factors and series resistance estimated by I-V and Cheung’s methods are compared. The discrepancy between barrier heights estimated from I-V and C-V methods is also explained.

Thermal annealing effects on electrical properties of Ir/Ru Schottky contacts on n-InGaN

Effects of annealing on electrical properties of Ir/Ru Schottky contacts on n-InGaN have been investigated by current-voltage (I-V) measurements. The Schottky barrier height (SBH) is found to be 0.61 eV for as-deposited Ir/Ru Schottky contacts. For the contacts annealed at 200 and 300°C, the SBH slightly increases and then slightly decreases after annealing at 400°C and 500°C. The series resistance (RS) can be determined using Cheungs method. Besides, the energy distributions of interface state densities are determined by using the Termans method. It is noted that the electrical properties of Ir/Ru Schottky contacts are improved after annealing at 300°C. Based on these results, it is clear that Ir/Ru Schottky contact is an attractive metallization scheme for the fabrication of InGaN-based device applications.