Abstract: A computer-implemented method may determine a sheet resistance of a base layer of a bipolar junction transistor (BJT). A computer-implemented method may estimate a quiescent current based on the sheet resistance of the base layer. A computer-implemented method may reject a power amplifier die based on the quiescent current not satisfying a threshold level.

Abstract: Apparatus and methods for evaporating metal onto semiconductor wafers are disclosed. One such apparatus can include an evaporation chamber that includes a wafer holder, such as a dome, and a test wafer holder that is separate and spaced apart from the wafer holder. In certain implementations, the test wafer can be coupled to a cross beam supporting at least one shaper. A metal can be evaporated onto production wafers positioned in the wafer holder while metal is evaporated on a test wafer positioned in a test wafer holder. In some instances, the production wafers can be GaAs wafers. The test wafer can be used to make a quality assessment about the production wafers.

Abstract: Apparatus and methods for uniform metal plating onto a semiconductor wafer, such as GaAs wafer, are disclosed. One such apparatus can include an anode and a showerhead body. The anode can include an anode post and a showerhead anode plate. The showerhead anode plate can include holes sized to dispense a particular plating solution, such as plating solution that includes gold, onto a wafer. The showerhead body can be coupled to the anode post and the showerhead anode plate. The showerhead body can be configured to create a seal sufficient to substantially prevent a reduction of pressure in the plating solution flowing from the anode post to holes of the showerhead anode plate.

Abstract: Apparatus and methods for uniform metal plating onto a semiconductor wafer, such as GaAs wafer, are disclosed. One such apparatus can include an anode and a showerhead body. The anode can include an anode post and a showerhead anode plate. The showerhead anode plate can include holes sized to dispense a particular plating solution, such as plating solution that includes gold, onto a wafer. The showerhead body can be coupled to the anode post and the showerhead anode plate. The showerhead body can be configured to create a seal sufficient to substantially prevent a reduction of pressure in the plating solution flowing from the anode post to holes of the showerhead anode plate.

Abstract: Apparatus and methods for uniform metal plating onto a semiconductor wafer, such as GaAs wafer, are disclosed. One such apparatus can include an anode and a showerhead body. The anode can include an anode post and a showerhead anode plate. The showerhead anode plate can include holes sized to dispense a particular plating solution, such as plating solution that includes gold, onto a wafer. The showerhead body can be coupled to the anode post and the showerhead anode plate. The showerhead body can be configured to create a seal sufficient to substantially prevent a reduction of pressure in the plating solution flowing from the anode post to holes of the showerhead anode plate.

Abstract: Apparatus and methods for uniform metal plating onto a semiconductor wafer, such as GaAs wafer, are disclosed. One such apparatus can include an anode and a showerhead body. The anode can include an anode post and a showerhead anode plate. The showerhead anode plate can include holes sized to dispense a particular plating solution, such as plating solution that includes gold, onto a wafer. The showerhead body can be coupled to the anode post and the showerhead anode plate. The showerhead body can be configured to create a seal sufficient to substantially prevent a reduction of pressure in the plating solution flowing from the anode post to holes of the showerhead anode plate.

Abstract: Apparatus and methods for evaporating metal onto semiconductor wafers are disclosed. One such apparatus can include an evaporation chamber that includes a wafer holder, such as a dome, and a test wafer holder that is separate and spaced apart from the wafer holder. In certain implementations, the test wafer can be coupled to a cross beam supporting at least one shaper. A metal can be evaporated onto production wafers positioned in the wafer holder while metal is evaporated on a test wafer positioned in a test wafer holder. In some instances, the production wafers can be GaAs wafers. The test wafer can be used to make a quality assessment about the production wafers.

Abstract: Apparatus and methods for evaporating metal onto semiconductor wafers are disclosed. One such apparatus can include an evaporation chamber that includes a wafer holder, such as a dome, and a test wafer holder that is separate and spaced apart from the wafer holder. In certain implementations, the test wafer can be coupled to a cross beam supporting at least one shaper. A metal can be evaporated onto production wafers positioned in the wafer holder while metal is evaporated on a test wafer positioned in a test wafer holder. In some instances, the production wafers can be GaAs wafers. The test wafer can be used to make a quality assessment about the production wafers.

Abstract: According to one embodiment, an NiV adhesion layer is deposited over the backside surface of a semiconductor substrate. The semiconductor substrate might comprise a group III-V compound semiconductor. The NiV adhesion layer can be deposited over the backside surface of the semiconductor substrate in, for example, a magnetron deposition system. In certain embodiments, the backside surface of the semiconductor surface may be cleaned to remove oxides from the surface prior to deposition of the NiV adhesion layer. After the NiV adhesion layer has been deposited, a gold seed layer is deposited over the NiV adhesion layer. Following deposition of the gold seed layer, a second gold layer is electroplated, or otherwise deposited, over the gold seed layer. In one embodiment, the invention is a structure fabricated according to the process steps described above.

Abstract: According to one embodiment, an NiV adhesion layer is deposited over the backside surface of a semiconductor substrate. The semiconductor substrate might comprise a group III-V compound semiconductor. The NiV adhesion layer can be deposited over the backside surface of the semiconductor substrate in, for example, a magnetron deposition system. In certain embodiments, the backside surface of the semiconductor surface may be cleaned to remove oxides from the surface prior to deposition of the NiV adhesion layer. After the NiV adhesion layer has been deposited, a gold seed layer is deposited over the NiV adhesion layer. Following deposition of the gold seed layer, a second gold layer is electroplated, or otherwise deposited, over the gold seed layer. In one embodiment, the invention is a structure fabricated according to the process steps described above.

Abstract: A method of diffusion of dopants (e.g. zinc) into III-V substrates (e.g. GaAs) using metal silicide and dopants (e.g. W.sub.x Si.sub.y :Zn) is disclosed. A cap layer (e.g. SiO.sub.2 or Si.sub.3 N.sub.4) is also used. The zinc tungsten silicide is formed by cosputtering zinc and tungsten silicide (W.sub.5 Si.sub.3). Applications include adjustment of threshold voltages in JFETs by rapid thermal pulsing of zinc into device channel regions and use of the zinc tungsten silicide as a base contact plus extrinsic base dopant source together with a nitride sidewall self-alignment.

Abstract: Thin film resistors formed from a metal silicon nitride film are provided in which tungsten, titanium, tantalum, and other group IV A, V A, and VII A metals are included. The silicon to metal ratio varying between about 0.1 and 10.0 and the nitrogen to metal ratio varying between about 0.1 and 10.0 provide sheet resistances which include the useful range of about 100 to over 10,000 ohms per square for films approximately 2,000 angstroms thick. Deposition of these materials by sputtering a metal silicide target in a nitrogen containing atmosphere, such as 20% nitrogen and 80% argon is also provided.

Abstract: Vertical AlGaAs heterojunction bipolar transistors (30) with planar structure together with fabrication methods therefor are disclosed. For an emitter (44) on top structure, the contacts (46) to the base (38) are formed by a diffusion of zinc dopants from the surface, and contacts (42) to the collector (34, 36) are formed by diffusions of sulfur dopants from the surface rather than by etch of connecting vias. Further, device isolation is also provided by zinc diffusions (54) rather than by mesa formation. These diffusions are by rapid thermal pulses.

Abstract: Increased barrier heights at metal(36)-semiconductor(32) contacts for semiconductors such as gallium arsenide by formation of an opposite doping type thin layer (34) on the semiconductor (32) surface by surface diffusion of dopants are disclosed. Preferred embodiments diffuse zinc 50 to 400 .ANG. into n type gallium arsenide (32) by rapid thermal pulses; then aluminum or titanium-platinum (36) contacts to the zinc doped layer (34) are deposited by evaporation and lift off.

Abstract: The dielectric, which is provided on either side of the active phosphor in an AC-driven electroluminescent display, is formed of a composite material which has both high dielectric constant and high resistivity. Preferably, a composite of titanum dioxide and alumina is used.