Influence of Argon-Plasma Etching of Single-Crystalline Silicon on Electroless Displacement Deposition of Metal Particles

Abstract

Fine metal particles can be formed on Si using electroless displacement deposition, by which Si wafers are simply immersed into a metalsalt solution containing HF. Depending on the kind of metal and the surface conditions of Si substrates, the particle density of the deposited metal varies widely. Especially, the Pt particle density greatly changes according to Si surface conditions. This study investigated the influence of Ar-plasma etching of Si on the Pt particle density. Single-crystalline n-Si (100) wafers were etched by Ar plasma using a radiofrequency glow discharge spectrometer. An amorphous Si layer was formed on etched Si surfaces. By immersing Ar-plasma-etched Si wafers in a H 2 PtCl 6 solution containing HF, Pt particles with particle density four hundred times higher than that for non-etched Si wafers were deposited. The Pt particle density was decreased by removing the amorphous layer and by chemical etching of the single-crystalline Si wafer. Results show that the influence of Ar-plasma-etching extended at least 0.5 μm to the interior of single-crystalline Si beneath the amorphous layer.

AFM Analysis for Initial Stage of Electroless Displacement Deposition of Silver on Silicon Surface

“…M n+ → M + nh + [1] Si + 6F -+ 4h + → SiF 6 2-(h + : hole) [2-1] and/or Si + 4HF 2 -+ 2h + → SiF 6 2-+ 2HF + H 2 This deposition method has been studied for applications to surface-enhanced infrared absorption reflection spectroscopy (7)(8)(9), the defect detection of Si wafers (10)(11)(12), metalassisted HF etching for the antireflection of Si solar cells (13)(14)(15), catalyst deposition for photoelectrochemical solar cells (16), and the surface activation for the autocatalytic electroless deposition of metal thin films on Si (17)(18)(19)(20). We previously reported the nucleation behavior of platinum, palladium, rhodium, copper, silver (Ag), and gold (5,6,21).…”