Measurement of Plasma Density for Control of Etching Profile in Inductively Coupled Plasma Etching of InP

We investigated the effect of the plasma density on the control of the etching profile in an inductively coupled plasma (ICP) etching of InP. It was found that the total ion density is not a good measure of the control of the etching profile. We have to take into account the quantity of each ion for etching profile control. We suggest that the etching profile of InP can be controlled by the in situ monitoring of the quantity of Cl + ions.