Etching of high dielectric constant ("high-k") materials in BCl3-Containing plasmas leaves behind a boron residue on underlying Si or SiO2 surfaces during the over-etching period. Boron is a p-type dopant and therefore it is best if it is removed prior to subsequent processing. We have investigated the effectiveness of H-2 plasmas in removing this boron-containing layer. Following etching of HfO2 thin films in a high-density BCl3 plasma, including a 60 s overetch period, samples were transferred under vacuum to a UHV chamber equipped with x-ray photoelectron spectroscopy (XPS). After observing areal density B-coverages of similar to 1 x 10(15) cm(-2) (equivalent of similar to 1 monolayer), the samples were transferred back to the plasma reactor for exposure to the H-2 cleaning plasma, and then reexamined by XPS. Optical emission spectroscopy was used to monitor B deposition on and removal from the plasma chamber walls. B deposition on the reactor walls during BCl3 plasma exposure reached saturated coverage in similar to 2 min. Following this, the H-2 plasma removed half of the B on the walls in 90 s and 90% in 320 s. B, was rapidly removed (< 5 s) from BCl3 plasma over-etched Si surfaces provided that the walls were first cleaned in the H-2 plasma, with the Si sample held in the UHV chamber during the chamber cleaning process. Conversely, it took much longer (similar to 180 s) to remove all detectable B on the sample surface if the sample and the reactor chamber wails were cleaned in the H-2 plasma at the same time. Apparently B is transported from the walls to the Si surface in this latter case. Etching rates of 22 and 1700 angstrom/min were measured for SiO2 and Si, respectively, in the H-2 cleaning plasma. The fast etching of Si allows still shorter cleaning times, or preferably dilute H-2 plasmas to be effective in removing B with less Si removal, provided the chamber walls are first cleaned in an H-2 plasma. (c) 2005 American Vacuum Society.