III-V semiconductor device dry etching using ECR discharges

Electron cyclotron resonance (ECR) discharges are characterized by high ion densities (<or approximately=10 12 cm -3 ) at low pressure ( approximately 1 mTorr) and by low ion energies (<or=15 eV). They are ideally suited for dry etching of III-V semiconductor devices, particularly when combined with additional RF biasing of the sample. In this paper the authors give examples of the use of this hybrid ECR-RF approach for etching of InP based devices in CH 4 /H 2 plasmas and GaAs-based devices in CCl 2 F 2 or PCl 3 plasmas. The systematics of damage introduction into HEMTs and HBTs using these mixtures have been studied and the authors slow that it is possible to dry etch such devices without creating ion-induced surface damage. A feature of ECR etching is the highly anisotropic nature of the pattern transfer. The role of the masking material in the subsequent morphology of the sidewall is also discussed.