Spectroscopic Studies on Electroless Deposition of Copper on a Hydrogen-Terminated Si(111) Surface in Fluoride Solutions

Abstract

The cementation or electroless deposition of copper on a hydrogen-terminated ͑H-͒Si͑111͒ surface in concentrated ammonium fluoride (NH 4 F) and dilute hydrofluoric acid ͑HF͒ solutions containing copper ion (Cu 2ϩ ) was investigated using attenuated total reflectance-Fourier transform infrared ͑ATR-FTIR͒ spectroscopy and X-ray photoelectron spectroscopy ͑XPS͒. When the H-Si͑111͒ sample was immersed in a 40% NH 4 F solution containing 10 M Cu 2ϩ , the ATR-FTIR showed a decrease in the monohydride ͑SiH͒, and XPS revealed the copper deposition and Si oxide formation as well as the existence of a small amount of fluorinated Si species on the H-Si͑111͒ surface. After the surface was rinsed with ultrapure water, the amounts of SiH and Si oxide decreased and increased, respectively, while the fluorinated Si species disappeared. Copper and Si oxide were observed on the Si surface even after being etched in a Cu

DME Dissociation Reaction on Platinum Electrode Surface: A Quantitative Kinetic Analysis by In Situ IR Spectroscopy

“…It was chemically deposited on the flat surface of a hemicylindrical Si prism. 17,20 Briefly, the Si surface was activated first by contacting with 0.5% HF containing 1 mM PdCl 2 , which can improve the adhesion of the deposited metal film to the Si substrate. Then, Pt was chemically deposited to form a 50 nm thick film with a commercially available plating solution ͑LECTROLESS PT100, Electroplating Engineering of Japan͒ at 60°C.…”

Photoanodic formation of an organic monolayer on a hydrogen-terminated Si(1 1 1) surface via Si–C covalent bond using a Grignard reagent and its application for one-step monolayer-patterning

“…7 These results showed that the coverage of the monolayer was not very high and the monolayer was not highly ordered. XPS measurements showed no clear peak at 103.2 eV corresponding to Si 4+ , 41,42 indicating that the oxidation of the underlying silicon surface did not take place.…”

Spectroscopic Studies on Electroless Deposition of Copper on Hydrogen-Terminated Si(111) Surface in NH4F Solution Containing Cu(II) Ions

“…There are two possible reduction processes on the Si surface in fluoride solutions. 10,11 One is a combination reaction of the two consecutive processes including the oxidized silicon as an intermediate.…”

“…16 To obtain hydrogen-terminated Si(111) surface, the ATR prism was immersed in 40% NH 4 F solution and dried in flowing nitrogen gas. The sample was immersed in copper containing 40% NH 4 F solution (10,20,50, and 100 µM Cu 2+ solution) for 3, 5, 15, and 20 min and dried in flowing nitrogen gas without the sample being rinsed by DI water except the case described otherwise.…”

“…12 The present result is in good agreement with some previous reports. 1,5,6,10,12 The same H-Si(111) surface was probed under nitrogen gas atmosphere by means of STM and the result is shown in Figure 3. The surface has a wide terrace of 50 nm or more with a step height of 3.1 Å.…”