Semiconductor etching methods

A method of etching into one or more epitaxial layers of respective semiconductor material(s) in a light-emitting diode (LED) semiconductor structure, wherein the or each semiconductor material is any of:

• GaAs, AlGaAs, InGaAs and GaAsP, the method comprising:
• placing a substrate having the semiconductor structure thereon onto a support table in a plasma processing chamber, the semiconductor structure carrying a patterned mask on the surface of the semiconductor structure distal from the support table;
• and process steps of:
• establishing a flow of an etch gas mixture through the plasma processing chamber;
• and
• generating a plasma within the plasma processing chamber and simultaneously applying a radio frequency (RF) bias voltage to the support table;
• whereby portion(s) of the semiconductor structure not covered by the patterned mask are exposed to the etch gas mixture plasma and are thereby etched to form at least one feature in the semiconductor structure;
• wherein more than 90% of the etch gas mixture consists of a mixture of silicon tetrachloride (SiCl4) and nitrogen (N2), and wherein the etch gas mixture comprises more nitrogen (N2) than silicon tetrachloride (SiCl4) and wherein the amount of N2 in the etch gas mixture is no more than three times the amount of SiCl4.

A method of etching into one or more epitaxial layers of respective semiconductor material(s) in a photodiode semiconductor structure, wherein the or each semiconductor material is any of:

• GaAs, AlGaAs, InGaAs and GaAsP, the method comprising:
• placing a substrate having the semiconductor structure thereon onto a support table in a plasma processing chamber, the semiconductor structure carrying a patterned mask on the surface of the semiconductor structure distal from the support table;
• and process steps of:
• establishing a flow of an etch gas mixture through the plasma processing chamber;
• and
• generating a plasma within the plasma processing chamber and simultaneously applying a radio frequency (RF) bias voltage to the support table;
• whereby portion(s) of the semiconductor structure not covered by the patterned mask are exposed to the etch gas mixture plasma and are thereby etched to form at least one feature in the semiconductor structure;
• wherein more than 90% of the etch gas mixture consists of a mixture of silicon tetrachloride (SiCl4) and nitrogen (N2), and wherein the etch gas mixture comprises more nitrogen (N2) than silicon tetrachloride (SiCl4) and wherein the amount of N2 in the etch gas mixture is no more than three times the amount of SiCl4.