Surface-Inhibiting Effect in Chemical Vapor Deposition of Boron–Carbon Thin Films from Trimethylboron

We use the ability to control surface chemistry in chemical vapor deposition (CVD) to deposit boron–carbon films into pores with an aspect ratio of 60:1 without clogging the opening, and into lateral trenches with ratios of up to 2000:1. In contrast to many other surface-controlled CVD processes, operating at low temperatures (100–250 °C) and pressures (10–1000 Pa), we use trimethylboron at a higher temperature (700 °C) and pressure (5000 Pa), affording a surface-inhibited CVD process in hydrogen ambient. We show that the deposition rate is highly dependent on the partial pressure of hydrogen; decreasing proportionally to the logarithm of the partial pressure. The surface-controlled effect is not encountered in argon ambient. We propose that this is explained by a competitive adsorption of growth species and inhibiting dihydrogen or atomic hydrogen species following a Temkin isotherm.