Abstract: A silicon carbide substrate is etched to form a tapered feature. The plasma etch step includes generating a plasma from an etchant gas mixture comprising at least one chlorine-containing component, at least one inert gas component and at least one passivation material precursor. The anisotropic etching of the substrate comprises deposition of a passivation material.

Abstract: A plasma etch step anisotropically etches a silicon carbide semiconductor substrate through an opening to produce a feature. The plasma etch step generates a plasma from an etchant gas mixture that includes at least one fluorine-containing component and chlorine gas. The etchant gas mixture can further include SiCl4, an oxygen-containing component, and/or inert gas component.

Abstract: A method of plasma etching a compound semiconductor substrate forms a feature. A first plasma etch step anisotropically etches the substrate through an opening to produce a partially formed feature having an opening and a bottom surface with a peripheral region. A second plasma etch step removes a region of the mask adjacent to the opening of the partially formed feature thereby causing rounding of the edges of the substrate at the opening of the partially formed feature. A third plasma etch step anisotropically etches the bottom surface of the partially formed feature through the opening of the mask while depositing a passivation material onto the mask and the opening of the partially formed feature to reduce a dimension of the opening of the partially formed feature. A plasma etch apparatus can be used to perform the method.

Abstract: A substrate with a mask formed thereon is provided. The substrate is formed from a compound semiconductor material. A first plasma etch step is performed to anisotropically etch the substrate through the opening to produce a partially formed feature having a bottom surface comprising a peripheral region. A second plasma etch step is performed to anisotropically etch the bottom surface of the partially formed feature through the opening while depositing a passivation material onto the mask so as to reduce a dimension of the opening. The reduction of the dimension of the opening causes an attenuation in etching of the peripheral region thereby producing a fully formed feature having a bottom surface comprising a central region and an edge region. The central region is deeper than the edge region of the bottom surface of the fully formed feature.