The Cu/n-GaAs schottky barrier diodes prepared by anodization process

Abstract

The metal-insulating semiconductor (MIS) Cu/n-GaAs diodes with thin anodic-insulating layer, which is formed by anodic oxidization on the n-GaAs substrate in aqueous 4C 2 H 6 O 2 ϩ 2H 2 O ϩ 0.1H 3 PO 4 electrolyte with pH ϭ 2.02; anodically untreated control Cu/n-GaAs diodes; and anodically treated Cu/nGaAs diodes (several steps of anodization in the same electrolyte followed by a dip in diluted aqueous HCl solution and a subsequent rinse in deionized water) have been prepared. The anodization has increased the barrier heights as well as the ideality factors. We have obtained barrier heights of approximately 0.68 eV, 0.90 eV, and 0.92 eV for the control sample, anodically treated sample, and MIS sample, respectively, adding the contribution caused by image-force effect only. Thus, the barrier height has been increased by at least 140 meV. Furthermore, we have calculated a mean tunneling-barrier height of ϭ 0.025 eV for the MIS Cu/n-GaAs Schottky barrier diode (SBD).

Electrical characterization of Au/3C-SiC/n-Si/Al Schottky junction

“…3 was fitted by both linear and a non-linear fitting functions and the plot of ln(I o /T 2 ) vs 1/T exhibits a non-linear behavior with R 2 = 0.999 value. This deviation in the Richardson plot indicates due to the presence of the spatially inhomogeneous BHs and potential fluctuations at the interface that consist of low-and high-barrier areas [17][18][19][20] and it will be later discussed in detail. The series resistance is another important parameter on the current-voltage characteristics and in series resistance case, for determination of diode parameters, we can use Cheung's method defined by the following relations [21],…”

Electrical and optical characteristics of Au/PbS/n-6H–SiC structures prepared by electrodeposition of PbS thin film on n-type 6H–SiC substrate

“…An ideality factor value of 1.37 can be originated from the presence of the PbS layer between Au and SiC layers [40][41][42][44][45][46][47][48][49]. The increase of 60 meV in the BH value may be ascribed to the presence of the PbS interlayer that modifies the effective BH by influencing the space charge region of the SiC [40][41][42][44][45][46][47][48][49]. As well-known, the interfacial layer in MS contacts plays an important role in the determination of the BH of the devices, and it can be a sensitive probe useful in establishing processes for minimizing surface states, surface damage and contamination.…”

“…Thus, this process may ultimately increase the quality of devices fabricated using the semiconductor. Thereby, it is known that the PbS film forms a physical barrier between the metal and SiC substrate, it protects the SiC surface from the metal [40][41][42]45].…”

“…We can explain as follows that the PbS interlayer modifies the effective BH by influencing the space charge region of the SiC [40][41][42]45]. It has been indicated above that the BH values of 0.97 eV for the reference sample (Au/n-6H-SiC) and 1.03 eV for the Au/PbS/n-6H-SiC sample have been obtained.…”

“…In metal/n-type semiconductor contacts, in the absence of the interface states, the negative charge Q m on the metal surface must be equal the positive space charge Q sc because the junction is electrically neutral. In the presence of the interface states, the neutrality condition becomes Q m + Q sc + Q ss = 0 [40][41][42]45]. The occupancy of the interface states is determined by the Fermi level which affects the change of the space charge Q sc in the depletion layer of the semiconductor, and thus the modification of the SBH in the diode with the PbS interlayer.…”