ELECTRON-CYCLOTRON-RESONANCE PLASMA-ETCHING OF INP AND RELATED MATERIALS IN BCL3

InP, InAlP and InGaP can be etched at rates of 0.5-0.8 mu m min(-1) in pure BCl3 discharges at high microwave powers (1000 W). The etch rate s are strong functions of focusing magnet current, microwave power, sa mple temperature and to the nature of additive gases. For example, InG aP etch rates a factor of two to three faster than for BCl3 alone are obtained when small additions (25% by flow) of N-2 or O-2 are added to enhance dissociation of the BCl3. As microwave power is increased the surface morphology of InP is degraded, while that of InGaP improves, InAlP is relatively resistant to surface changes between 250 and 1000 W of microwave power. The sidewalls of etched features are extremely s mooth and suitable for a variety of photonic devices.