A tube mat made of elastomer material in the form of an extrudate includes first and second front faces which are arranged in a vertical or angled manner in relation to the extrusion direction. Apparatus and method aspects according to other embodiments of the invention also are disclosed. The switching is arranged to transfer to the compensating-capacitor an injection error charge produced by the charging switch, and then to isolate the injection error charge on the compensating-capacitor from the load-capacitor. Thereafter, a hardmask layer is applied and patterned on the wafer; and the wafer is then directionally etched with the patterned hardmask to etch trenches in the monocrystalline silicon.