Semilab Semiconductor Physics Laboratory Co., Ltd.

Bret Schrayer

Jacek J Lagowski

Marshall D Wilson

Alexandre Savtchouk

Carlos Almeida

Dmitriy Marinskiy

Methods of characterizing semiconductor doping in a wide bandgap semiconductor sample include: measuring an initial value, V, of a surface voltage at a region of a surface of the semiconductor sample in the dark; charging the region to deep depletion in the dark by depositing a prescribed corona charge at the region; measuring the surface voltage value in the dark at the region after charging; illuminating the charged region with light of a specific photon flux, f, having a photon energy above the semiconductor bandgap sufficient to generate free minority carriers in the semiconductor sample causing photoneutralization of the corona charge; monitoring of a photoneutralization induced corona charge decay at the region vs. illumination time, t, using a noncontact time resolved measurement of surface voltage, V(t); analyzing the monitored time resolved surface voltage decay data V(t) to determine values for a parameter characteristic of a photoneutralization induced corona charge decay at the regions; and using the parameter at a specific photon flux, ϕ, to characterize the property of the semiconductor at the region based on the values of the parameter.

Semiconductor doping characterization method using photoneutralization time constant of corona surface charge

Methods of characterizing semiconductor doping in a wide bandgap semiconductor sample include: measuring an initial value, V, of a surface voltage at a region of a surface of the semiconductor sample in the dark; charging the region to deep depletion in the dark by depositing a prescribed corona charge at the region; measuring the surface voltage value in the dark at the region after charging; illuminating the charged region with light of a specific photon flux, ƒ, having a photon energy above the semiconductor bandgap sufficient to generate free minority carriers in the semiconductor sample causing photoneutralization of the corona charge; monitoring of a photoneutralization induced corona charge decay at the region vs. illumination time, t, using a noncontact time resolved measurement of surface voltage, V(t); analyzing the monitored time resolved surface voltage decay data V(t) to determine a photoneutralization time constant, τ; and using the photoneutralization time constant, τat a specific photon flux, ƒ, as a semiconductor doping index and characterizing a semiconductor doping concentration at the region based on its value.

Methods of characterizing electrical properties of a semiconductor layer structure on a wafer with topside semiconductor layers on an insulating or semi-insulating substrate, the semiconductor layer structure including a high electron mobility transistor (HEMT) heterostructure with a two-dimensional electron gas (2DEG) at a heterointerface between the semiconductor layers of the heterostructure. The methods include: (a) physically contacting the topside of the wafer within a narrow border zone at an edge of the wafer with a flexible metal cantilever electrode of a contacting device, wherein the flexible metal cantilever electrode contacts one or more of the semiconductor layers exposed at the narrow border zone so that the flexible metal cantilever electrode is in electrical contact with the 2DEG; and (b) applying corona charge bias and measuring a surface voltage of the semiconductor layers using a non-contact probe while maintaining the electrical contact with the 2DEG. The physical contacting to the topside of the wafer is noncontaminating and noninvasive to the semiconductor layers.

Topside contact device and method for characterization of high electron mobility transistor (HEMT) heterostructure on insulating and semi-insulating substrates

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Bret Schrayer