what is film purity contamination how gases degrade films

Film PURITY = how free the film is of unwanted elements (oxygen, moisture, carbon, residual gases). Contamination degrades the film's electrical properties (higher resistivity) and reliability, and can cause device failures. Sources: impure source gases, moisture/oxygen leaks in the chamber, residual gases, poor chamber vacuum. Why GPS cares: purity problems show up as field quality issues — and this is YOUR home turf (you did GCMS chemical cleanliness work). The key line: 'Contamination isn't always visible — a film can look fine and be electrically wrong because of a trace contaminant, which is why I check composition and cleanliness, not just appearance.' Your GCMS + ICP-OES background makes this a differentiator. Show you know how to detect and prevent it.