Thermal Annealing Effects on the Electrical and Structural Properties of Ni/Pt Schottky Contacts on the Quaternary AlInGaN Epilayer

Abstract

contacts were placed on a quaternary Al 0.84 In 0.13 Ga 0.03 N epilayer. The electrical and structural properties of the asdeposited Pt/Au, Ni/Au, Ni/Pt/Au and annealed Ni/Pt/Au Schottky contacts were investigated as a function of annealing temperature using currentvoltage (I-V), capacitance-voltage (C-V), and high resolution x-ray diffraction measurements (HR-XRD). According to the I-V, Norde, and C-V methods, the highest Schottky barrier height (SBH) was obtained for the Pt/Au (0.82 eV (I-V), 0.83 eV (Norde), and 1.09 eV (C-V)) contacts when they were compared with the other as-deposited Schottky contacts. The estimated SBH of the annealed Ni/Pt/Au Schottky contacts, calculated from the I-V results, were 0.80 eV, 0.79 eV, and 0.78 eV at 300°C, 400°C, and 500°C, respectively. The SBH decreases with an increase in the annealing temperature up to 500°C compared with that of the as-deposited Ni/Pt/Au Schottky contact. The observed extra peaks in the annealed samples confirm the formation of a new interfacial phase at the interface. However, the diffraction patterns of the annealed Schottky contacts did not change as a function of the annealing temperature. The higher ideality factors values were obtained for as-deposited Pt/Au (5.69), Ni/Au (6.09), and Ni/Pt/Au (6.42) Schottky contacts and annealed Ni/Pt/Au (6.42) Schottky contacts at 300°C (6.89), 400°C (7.43), and 500°C (8.04). The higher n results can be attributed to current-transport mechanisms other than thermionic emission, such as dislocation related tunneling.

Medium Energy Carbon and Nitrogen Ion Beam Induced Modifications in Charge Transport, Structural and Optical Properties of Ni/Pd/n-GaN Schottky Barrier Diodes

“…When the incident ion comes to rest in the semiconductor, a damaged layer is produced along its trajectory, which leads to increased values of R S [46]. The values of n are higher than unity for the pristine sample [36,47,48], which may be a result of the barrier inhomogeneities or due to tunneling and generation-recombination (G-R) currents, and it further increases with higher fluence due to increase in tunneling current. The reverse leakage current has increased significantly for the fluence of 1 × 10 13 ions/cm 2 of 600 keV C 2+ and 650 keV N 2+ ion irradiation.…”

Plasma and Annealing Treatments to Form Height-Barrier Ni-Based Schottky Contact to n-GaN

“…12,13 For example, poor Schottky contacts in GaN-based HEMTs resulted in serious leakage current, thereby degrading the gate current characteristics and increasing power consumption. 14 As for n-GaN, various metal schemes consisting of single and/or multilayers (with high work functions) have been widely investigated in order to produce high Schottky-barrier-height (SBH) and thermally stable contacts. [14][15][16] Among these schemes, nickel (Ni)-based schemes [15][16][17][18][19][20] have been widely investigated because of its high work function and thermal stability.…”

“…14 As for n-GaN, various metal schemes consisting of single and/or multilayers (with high work functions) have been widely investigated in order to produce high Schottky-barrier-height (SBH) and thermally stable contacts. [14][15][16] Among these schemes, nickel (Ni)-based schemes [15][16][17][18][19][20] have been widely investigated because of its high work function and thermal stability. For instance, capacitance-voltage (C-V), currentvoltage (I-V) and internal photoemission examinations of the annealed Ni contacts to n-GaN homoepitaxial layer (carrier concentration, n e , = 5.0 × 10 15 cm −3 ) exhibited that the SBH reduced from 1.14 to 1.11 eV as the temperature increased from 223 to 373 K. 16 The decrease in the SBH was attributed to the shrinkage of the bandgap in GaN with increasing temperature.…”