Patent ID: 8118941

Claim:
A semiconductor processing reactor part for defining a reaction chamber for processing a semiconductor substrate, the reactor part comprising: a front surface configured to delimit at least part of the reaction chamber; a back surface on a side of the reactor part opposite the front surface; a plurality of holes in the reactor part, the holes extending from the front surface to the back surface, the holes each having an opening on the back surface, the opening having a first width, the holes comprising: a constriction having a passage having a constriction length and a constriction width transverse to the constriction length, the constriction width in a plane substantially parallel to a plane of the first width, wherein the constriction width is smaller than the first width, wherein a constriction ratio of the constriction length to the constriction width is about 15:1 or less; and a first portion which opens directly to the back surface, the first portion having a first length and the first width, the first length extending between the constriction and the opening, wherein a first ratio of the first length to the first width is about 15:1 or less; and a protective coating on walls of the holes and on the front and back surfaces.