Submicron suspended structures based on A(III)B(V) epitaxial layers

A technological process has been described for fabrication of suspended structures on GaAs substrate with AlGaAs/GaAs epitaxial multi-layers deposited by the AP MOVPE method. The patterns of beams and bridges with various dimensions were made by the photolithography method. The structures were fabricated by wet chemical etching in two systems of solutions based on phosphoric or citric acid with hydrogen peroxide. The former one enabled etching through the deposited epitaxial layers down to the GaAs substrate. The latter one allowed a selective etching of GaAs over AlGaAs. In effect, a beam made of AlGaAs layer was released and formed the suspended structure. As an etching mask, AZ 1813 positive photoresist was used. A series of rectangular beams with various planar dimensions and submicrometer thicknesses was fabricated. The elaborated process may be used for fabrication of suspended structures for various applications.