A low pressure hyperbaric chambers and methods of using same are disclosed. An example mounting frame for holding electronic devices includes an elongated extruded body having two substantially parallel wiring cavities extending along a length of the body and separated by a wall within the body. A motor oscillates the ice forming tray about a longitudinal axis at a frequency of about 0. The vibration energy is stopped for a time sufficient for re-solidification of the liquefied material, and then the core is removed. A plurality of dopant atoms are selectively implanted into the array portion so as to increase a threshold voltage which is required to develop a conducting channel through the valve region.