A two-step, chlorination/alkylation procedure has been used to convert the surface Si-H bonds on NH 4 F ͑aq͒ -etched ͑111͒-oriented Si wafers into Si-alkyl bonds of the form Si-C n H 2nϩ1 (nу1). The electrical properties of such functionalized surfaces were investigated under high-level and low-level injection conditions using a contactless rf apparatus. The charge carrier recombination velocities of the alkylated surfaces were Ͻ25 cm s Ϫ1 under high-level and low-level injection conditions, implying residual surface trap densities of Ͻ3ϫ10 9 cm Ϫ2 . Although the carrier recombination velocity of hydrogen-terminated Si͑111͒ surfaces in contact with aqueous acids is Ͻ20 cm s Ϫ1 , this surface deteriorates within 30 min in an air ambient, yielding a high surface recombination velocity. In contrast, methylated Si͑111͒ surfaces exhibit low surface recombination velocities in air for more than 4 weeks. Low surface recombination velocities were also observed for Si surfaces that had been modified with longer alkyl chains.

We describe a method for growing uniform, covalently attached polymer onto crystalline Si(111) surfaces. H-Terminated Si was first chlorinated, and the surface-bound chlorine was then replaced by a terminal olefin using a Grignard reaction. A ruthenium ring-opening metathesis polymerization catalyst was then crossed onto the terminal olefin, and the resulting surface was subsequently immersed into a solution of monomer to produce the desired surface-attached polymer. The method provides a direct linkage between the polymer and the Si without the presence of an electrically defective oxide layer. Growth of the polymeric layer could be controlled by varying the concentration of monomer in solution, and polynorbornene films between 0.9 and 5500 nm in thickness were produced through the use of 0.01-2.44 M solutions of norbornene.