Before cleaning: GaN with a tight structure after vapor deposition is attached to the quartz surface. It cannot be sprayed off by high-pressure water gun cleaning. It cannot be wiped off with red pickle cloth.

Soak and clean with FGTC04 at 60°C: Heating with water is required. Do not put FGTC04 in stainless steel or glass containers, because free metal ions will accelerate the deterioration of FGTC04. Therefore, it is recommended to put it in a plastic container and heat it with water.

After cleaning: GaN is loosened from the quartz surface after soaking in FGTC04 heated to 60°C for 30 minutes. At this time, it can be easily removed by spraying with a high-pressure water jet, or with a white/red pickle cloth.