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The uncertainty calculation for on-wafer 1-port S-Parameter measurements due to the uncertainty of coplanar on-chip calibration standards is presented. Analytical expressions for the sensitivities are used and applied for typical fabrication tolerances of monolithic integrated on-chip structures. The method is verified for OSM calibration by means of simulations with a commercial calibration software as well as by measurements, where test-structures with artificial errors were used. In each case the analytically calculated deviation is compared to a numerical approach and good agreement is found. All results are given for a MMIC process on GaAs, but can be adopted for other technologies.
Measurement uncertainties due to non-ideal calibration standards for unknown thru calibration
(2013)
This paper investigates the impact of possible parameter extraction errors caused by inaccurate definition of the calibration reference impedance of in-situ multiline TRL. Two calibration sets implemented on GaAs and Si/SiGe:C wafer processes were quantitatively analyzed. Obtained results demonstrated that for most practical cases, the desired 5%-level of confidence of extracted parameters of high-reflective devices can easily be achieved without additional efforts. Thus, implementation of the in-situ TRL into a characterization workflow of high-performance microwave devices can be significantly simplified.
AlGaN/GaN heterostructure field effect transistors (HFETs) were irradiated with 2 MeV protons, carbon, oxygen, iron and krypton ions with fluences ranging from 1 × 109 cm−2 to 1 × 1013 cm−2. DC, pulsed I–V characteristics, loadpull and S-parameters of the AlGaN HFET devices were measured before and after irradiation. In parallel, a thick GaN reference layer was also irradiated with the same ions and was characterized by X-ray diffraction, photoluminescence, Hall measurements before and after irradiation. Small changes in the device performance were observed after irradiation with carbon and oxygen at a fluence of 5 × 1010 cm−2. Remarkable changes in device characteristics were seen at a fluence of 1 × 1012 cm−2 for carbon, oxygen, iron and krypton irradiation. Similarly, remarkable changes were also observed in the GaN layer for irradiations with fluence of 1 × 1012 cm−2. The results found on devices and on the GaN layer were compared and correlated.
AlGaN/GaN heterostructure field effect transistors (HFETs) were irradiated with protons as well as carbon, oxygen, iron and krypton ions of high (68 and 120 MeV) and low (2 MeV) energy with fluences in the range from 1x107 to 1x1013 cm-2. High energy irradiation with protons, carbon and oxygen produced no degradation in devices while krypton irradiation at the fluence of 1x1010 cm-2 resulted in a small reduction of 2% in the transconductance. Similarly, for GaN samples irradiated with protons, carbon and oxygen at high energy no changes were seen by XRD, PL and Hall effect, while changes in lattice constant and a reduction in PL intensity were observed after irradiation with high energy krypton. Low energy irradiation with carbon and oxygen at a fluence of 5x1010 cm-2 results in small change in the device performance while remarkable changes in device characteristics are seen at a fluence of 1x1012 cm-2 for carbon, oxygen, iron and krypton irradiation. Similarly changes are also observed by XRD, PL and Hall effect for the thick GaN layer irradiated at the fluence of 1x1012 cm-2. The device results and GaN layer properties are strongly correlated.
