Low-pressure discharges are discharges made under gas pressures from a few millitorr to a little less than atmospheric. They have the benefit of less power requirement of sustenance of the discharge as volume-recombination rates are lower.

It is easier to achieve uniform discharges at low pressure. Normally, the system is pumped down and only necessary plasma gases are then flown into the plasma chamber. Argon

Argon

Argon is a chemical element represented by the symbol Ar. Argon has atomic number 18 and is the third element in group 18 of the periodic table . Argon is the third most common gas in the Earth's atmosphere, at 0.93%, making it more common than carbon dioxide...

 is a typical background gas because it has low ionization potential and therefore is easier to break down and sustain.

Most discharges used in the semiconductor industry

Semiconductor industry

The semiconductor industry is the aggregate collection of companies engaged in the design and fabrication of semiconductor devices. It formed around 1960, once the fabrication of semiconductors became a viable business...

 employ low-pressure plasmas

Plasma (physics)

In physics and chemistry, plasma is a state of matter similar to gas in which a certain portion of the particles are ionized. Heating a gas may ionize its molecules or atoms , thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions...

.