Metal electrodeposition on semiconductors

Electroplating of Semiconductor Materials for Applications in Large Area Electronics: A Review

The attributes of electroplating as a low-cost, simple, scalable, and manufacturable semiconductor deposition technique for the fabrication of large-area and nanotechnology-based device applications are discussed. These strengths of electrodeposition are buttressed experimentally using techniques such as X-ray diffraction, ultraviolet-visible spectroscopy, scanning electron microscopy, atomic force microscopy, energy-dispersive X-ray spectroscopy, and photoelectrochemical cell studies. Based on the results of structural, morphological, compositional, optical, and electronic properties evaluated, it is evident that electroplating possesses the capabilities of producing high-quality semiconductors usable for producing excellent devices. In this paper we will describe the progress of electroplating techniques mainly for the deposition of semiconductor thin film materials and their treatment processes, and fabrication of solar cells.

Electrochemical fabrication and interfacial charge-transfer process of Ni/GaN(0001) electrodes

The electrodeposition of Ni on single-crystal n-GaN(0001) film from acetate solution was investigated using scanning electron microscopy, X-ray diffraction, energy dispersive X-ray analysis, atomic force microscopy, and electrochemical techniques. The as-deposited Ni/n-GaN(0001) had a flat band potential of Ufb = -1.0 V vs. Ag/AgCl, which was much lower than that of bare GaN(0001). That is, a more feasible charge-transfer process occurred at the Ni/n-Ga(0001) interface. On the basis of a Tafel plot, an exchange current density of ∼1.66 × 10(-4) mA cm(-2) was calculated. The nuclei density increased when the applied potential was varied from -0.9 V to -1.2 V and, eventually the whole substrate was covered. In addition, the current transient measurements revealed that the Ni deposition process followed instantaneous nucleation in 5 mM Ni(CH3COO)2 + 0.5 M H3BO3.

One-dimensional nano-interconnection formation

Interconnection of one-dimensional nanomaterials such as nanowires and carbon nanotubes with other parts or components is crucial for nanodevices to realize electrical contacts and mechanical fixings. Interconnection has been being gradually paid great attention since it is as significant as nanomaterials properties, and determines nanodevices performance in some cases. This paper provides an overview of recent progress on techniques that are commonly used for one-dimensional interconnection formation. In this review, these techniques could be categorized into two different types: two-step and one-step methods according to their established process. The two-step method is constituted by assembly and pinning processes, while the one-step method is a direct formation process of nano-interconnections. In both methods, the electrodeposition approach is illustrated in detail, and its potential mechanism is emphasized.

Electrochemical Deposition of Metals on Semiconductors

The general concepts governing the electrochemical deposition of metal films on semiconductors are discussed, and recent results on the fabrication of Schottky junctions consisting of silicon electrodeposited with platinum, copper and gold are presented. In order to obtain good adherent metal films, the density of nuclei should be high and the films should be grown at low current densities where the charge transfer process is rate limiting. This situation can be realized using potential controlled electrochemical deposition. For metal deposition on silicon, the surface should be pretreated in HF to dissolve the oxide layer. Furthermore, the surface should be stable during deposition which can be achieved by tailoring the deposition solutions and by using electrochemical deposition at negative potentials. It is shown that by using this approach, n-type silicon / Pt, Au, and Cu Schottky junctions can be fabricated of a quality comparable to that of junctions prepared by sputter and vapor deposition techniques.

The Initial Stages of Metal Deposition on Metal and Semiconductor Electrodes Studied byIn SituStm

The deposition of Cu onto Au(100) and of Pb onto n- Si(111) electrodes from aqueous solutions has been monitoredin situby scanning tunneling microscopy. In the first case, a bcc structure of the Cu overlayer is observed, which allows pseudomorphic growth on Au(100) up to the 10th layer. Then a slow structural transition to fee begins. In contrast, Pb on Si(111) is shown to deposit as 3D crystallites with flat (111) terminated surfaces.