Boron-carbon thin films were deposited on silicon substrates in a horizontal hot-wall CVD reactor with a base pressure below 9 x 10 -5 Pa. The CVD rector has a SiC coated graphite susceptor which is inductively heated. The temperature was monitored by a pyrometer (Heitronics KT18.04, range 300-1,300 °C) pointing into a hole drilled in the backside of the susceptor. The process pressure was regulated by the mean of a throttle valve. Trimethylboron (TMB, B(CH3)3), 99.5% from Voltaix/Air Liquide Advanced Materials, was used as a single source precursor for CVD of B-C films. In a few experiments a mixture of TMB and triethylboron (TEB, B(CH2CH3)3), semiconductor grade quality from SAFC Hitech, were used as precursors. The trialkylborons were diluted in either Ar (99.9997%) or H2 (purified by a palladium membrane) carrier gas. A quartz glass gas liner was used for some comparing experiments with our previous work, 8 and when a combination of TMB and TEB was used. The use of a liner was observed to increase the growth rate by a factor of 2.9. Films were deposited onto 1 x 1 cm 2 Si(100) substrates which were cleaned in acetone and ethanol at 80 °C during 5 min each, in ultrasonic baths. The substrates were heated to deposition temperature in the deposition ambient, Ar or H2. The temperature was stabilized for five minutes prior to deposition, which was started by introducing the trialkylborons into the deposition chamber. High aspect ratio (AR) silicon DRAM structures (AR = 60:1 with 110 nm diameter) and Lateral High Aspect Ratio (LHAR) PillarHall® test chips developed and sold by VTT Technical Research Center of Finland(Nominal AR from 2:1 to 10048:1 with 500 nm gap) were used to investigate the conformality capabilities of the deposition process. The experimental conditions were identical to those applied for growth on Si substrates but excluding cleaning prior to deposition. The thickness of the deposits was measured by cross section Scanning Electron Microscopy (SEM, Leo 1550 Gemini). The microscope was operated with an accelerating voltage of 5 kV and an in-lens detector. X-ray photoelectron spectroscopy (XPS, Kratos Analytical AXIS Ultra DLD) was used to estimate the boron and carbon contents in the films. The spectrometer was operated at a base pressure of 1.5 x 10 -7 Pa, using Al Kα (1486.6 eV) radiation. The CasaXPS software (version 2.3.16) was used for quantitative analysis XPS data.