MAGNETRON ION ETCHING OF INP USING MIXTURE OF METHANE AND HYDROGEN AND ITS COMPARISON WITH REACTIVE ION ETCHING

Magnetron ion etching (MIE) of InP has been studied using methane and hydrogen. These results of the first study are compared with those obtained with reactive ion etching (RIE) using the same gases in the same machine but without the magnet. The advantages of the MIE system demonstrated here include etching rates about three to four times higher and a lower degree of acceptor passivation (reduction in carrier concentration of etched surface), a low self-bias of between 70-200 V, and a resulting etched surface which is very smooth. Moreover, it is found that RIE and MIE give very similar degree of passivation depths, provided sample temperature during etching does not exceed 60-degrees-C. However, MIE is favored because of higher etch rates. The degree of passivation in the MIE also depends on the percentage of methane used in the process. Anisotropic etching of InP with the MIE can be achieved under certain condition of high pressure, but in conjunction with reduced etch rate and degraded surface morphology.