Abstract: The present invention provides a method for manufacturing bipolar transistors having reduced parasitic resistance and therefore improved performance compared to conventionally made bipolar transistors. Dry etching of a compound semiconductor in the transistor allows a perimeter of the compound semiconductor layer to be substantially coextensive with a perimeter of an overlying metal layer. This, in turn, reduces the gap between the compound semiconductor and subsequently deposited metal layer to be minimized, thereby reducing the parasitic resistance of the bipolar transistor.

Abstract: A method for fabricating a bipolar transistor includes forming a vertical sequence of semiconductor layers, forming an implant mask on the last formed semiconductor layer, and implanting dopant ions into a portion of one or more of the semiconductor layers. The sequence of semiconductor layers includes a collector layer, a base layer that is in contact with the collector layer, and an emitter layer that is in contact with the base layer. The implanting uses a process in which the implant mask stops dopant ions from penetrating into a portion of the sequence of layers.

Abstract: A method for making an ICD or MEOD structure includes dry etching a structure to produce one or more via holes in an upper layer of the structure. The dry etching step stops on a metal layer that underlies the upper layer in the structure. The method also includes cleaning the dry etched structure with an aqueous solution that includes hydrogen peroxide and either an ammonium salt or an amine salt.