Methods of manufacture and surface treatment of semiconductor structures

Abstract

A method of surface treatment of a semiconductor structure comprising: Step S401) providing a substrate (30, fig. 1) comprising a gallium nitride-based material on a support table (14, Fig. 1), wherein a distal surface of the substrate is shaped to define features having side walls oriented non-parallel to the plane of the substrate; Step S402) establishing etching gases to plasma etch the gallium nitride-based material, whereby an outer layer is removed from at least part of the side walls of the features; and Step S403) during the etching, establishing a set of simultaneous process parameters including: controlling temperature of the support table to be at least a minimum 120ºC; controlling the electrical state of the support table so that no radio frequency, or an RF bias with a maximum power of 200 W or less, is applied to the substrate table. Other processing parameters may include controlling pressure inside a plasma processing chamber, controlling the rate of flow of the etch gases. [Fig. 4]