Analysis and path localization of gate current in AlGaN/GaN HEMTs using low frequency noise measurements and Optical Beam Induced Resistance Change technique

International audienceGaN based transistors' performance and reliability status are largely sensitive to gate conduction mechanisms and surface charges induced by spontaneous and piezoelectric effects. Understanding leakage current origin and kinetic is the key of knowledge for improving GaN technologies. Therefore, room temperature Low Frequency Noise (LFN) and Optical Beam Induced Resistance Change (OBIRCh) measurements have been investigated on the gate current of AlGaN/GaN High Electron Mobility Transistors (HEMTs). LFN measurements are performed under two configurations: the Schottky diode is measured at open drain, and the transistor is investigated in the saturated region (V DS =8V). On the other hand, the application of the OBIRCh imaging technique is performed on the Schottky diode versus the same gate voltages than for the LFN. This paper focuses on the behavior of the gate-source region of the Schottky diode and on the gate-source and gate-drain regions of the transistor. From the LFN measurements, it is found that the carriers contributing to I GS are following the same path between gate and source for both configurations (diode, transistor) under elevated reverse gate-source voltage. As from OBIRCh measurements, a spots spread transmit an increase in the current conduction area on the gate width when V GS decreases (toward high reverse biases). The results allow correlation between these two techniques

Backside failure analysis of GaAs MMIC ASICs

A case study of backside failure analysis is performed on failed MMIC ASIC devices sealed in SOP packages. The use of Benzocyclobutene (BCB) as a dielectric material, which is etched during wet etch front-side decapsulation, motivated the proposed backside approach. Due to the transparency of the GaAs substrate to near infrared wavelengths, innovative optical defect localization techniques can be used. In this paper we present the successful application of Thermal Laser Stimulation (OBIRCH, TIVA) to rapidly, non-destructively and precisely localize the defects through the GaAs substrate. Backside delayering allowing defect observation and revelation is also discussed. Finally, an electrical interpretation of the failure and the corrective actions are presented

Gate defects in AlGaN/GaN HEMTs revealed by low frequency noise measurements

International audienceFrom the last decade, Nitride-based High Electron Mobility Transistors (HEMTs) have demonstrated excellent electrical and noise performances to address transceivers modules. Within this paper, a discussion on the low frequency noise on the gate access (i.e. gate current spectral density S IG) in the frequency range of 1Hz-100kHz is presented. S IG spectra reveal different signatures according to the configuration of biasing of the transistor, and to the dimensions of the transistor: the noise of the Schottky diode is studied alone (under open drain configuration), and compared with S IG of the transistor biased in the saturated region (at V DS =8V). Two designs of devices are tested: research-level devices featuring single gate finger are compared with commercial devices featuring four gate fingers, where each finger is four times larger (i.e. 16 times larger gate width than research level devices). The two sets of devices followed the same fabrication process. It is found that whatever the sizing and the gate pad configuration of the devices, the LFN spectra observed on each set of transistors feature identical signatures. The leakage carriers are following the same path between the gate and source accesses. LFN can be used as an accurate tool to discriminate between conduction mechanisms of devices, and to help to understand what are the underlying mechanisms leading to the conduction of the Schottky diode (and thus to its degradation). Moreover, it is shown that the S IG measurements under transistor biasing conditions can be correlated to the gate current spectral density in diode mode: the leakage current zone can also be tracked under this biasing operating mode

Analysis of current collapse effect in AlGaN/GaN HEMT: experiments and numerical simulations

In this work, current collapse effects in AlGaN/GaN HEMTs are investigated by means of measurements and two-dimensional physical simulations. According to pulsed measurements, the used devices exhibit a significant gate-lag and a less pronounced drain-lag ascribed to the presence of surface/barrier and buffer traps, respectively. As a matter of fact, two trap levels (0.45 eV and 0.78 eV) were extracted by trapping analysis based on isothermal current transient. On the other hand, 2D physical simulations suggest that the kink effect can be explained by electron trapping into barrier traps and a consequent electron emission after a certain electric-field is reached

Evidence of relationship between mechanical stress and leakage current in AlGaN/GaN transistor after storage test

International audienceIn this paper, leakage current signatures in AlGaN HEMT are studied after storage at 300°C. By comparing gate pad topology and by localized FIB cuts, Optical Beam Induce Resistance Change (OBIRCh) analysis was used to localize current path. Results tend to indicate that mechanical stresses in the gate structure strongly influences the leakage current of the transistor. Electrical characterization of the gate to source diode over temperatures supports the discrimination of the conduction mechanisms like thermionic field emission, Fowler-Nordheim or Poole-Frenkel. The OBIRCh analysis technique, widely used in silicon technology, appears to be a very efficient tool to localize leakage paths, in particular for HEMT topology with source terminated field plate

1998 Proceedings. Ohio Grape-Wine Short Course

The dollars and sense of starting a small winery / Chris Stamp -- You have the key, now where is the lock? You have the answer, now what was the question? / David Whiting -- Winery design and equipment / Domenic Carisetti -- Use of oak chips in winemaking / Bill Butler -- Matching wine style with your market / Edward Boas -- Open house--riesling reception / Roland Riesen -- 1997 vineyard survey / The Ohio Grape Team -- Economics of Midwestern grape production / Bruce Bordelon -- The economics of grape growing in Ohio / Gene Sigel -- The importance of reserves for rapid initial development of grapevines, shoots and berry set / Steven McArtney and Dave Ferree -- Influence of gibberellin sprays and leaf removal on vignoles / Dave Ferree, Steven McArtney and Mike Ellis -- Controlling color deterioration in blush wines / Jim Gallander, Roland Riesen and Todd Steiner -- Understanding and controlling powdery mildew and phomopsis cane and leaf spot of grape / Mike Ellis -- Managing late harvest and ice wines in the vineyard and winery / Ron Giesbrecht -- Ice wine production at Valley Vineyards / Greg Pollman -- The production of affordable ice wine / Chris Stamp -- A simple guide to sparkling wine production / Claudio Salvador -- Vineyard establishment in Wayne County Ohio / Andy Troutman -- New ideas in vineyard drainage / Gene Sigel -- Trellis and training systems for Midwest cultivars / Bruce Bordelon -- Soil and plant analyses / Maurus Brown -- Monitoring and control of grape pests in Ohio vineyards with insect attractants / Roger Williams, Dan Fickle, Chris Gertz -- Developing focus for vegetation management extension and research in vineyards / Douglas Doohan -- Grape cultivar selections for Ohio / Dave Ferree and Roland Riesen -- Ferrante Winery's need for grapes / Nick Ferrante -- Principles of wine stabilization / J. F. Gallander -- Working with a distributor / Jane Butler -- Vintners quality alliance; Ontario's success story / Angelo Pava

Proceedings. Ohio Grape-Wine Short Course, 1987

Fresh concord juice marketing / Larry Lockshin -- Reducing the use of sulfur dioxide in winemaking / William D. Edinger -- Crown gall in grapes / R. N. Goodman -- Understanding seedlessness in grapes / Craig K. Chandler -- Grape root borer--a potential new insect pest in Ohio / R. N. Williams, S. R. Alm, D. M. Pavuk and F. F. Purrington -- The use of potassium sorbate and ascorbic acid in wine / Thomas R. Schmidt -- Status of sulphur dioxide / Domenic Carisetti -- Factors affecting grapevine bud cold hardiness / Tony K. Wolf -- Preservation of fresh Concord juice / C. L. Stamp, J. F. Gallander and J. F. Stetson -- Epidemiology of downy mildew of grape / N. Lalancett, M. A. Ellis and L. V. Madden -- Influence of bacterial strains on the induction of malolactic fermentation / J. F. Gallander, R. R. Breen and J. A. Jindra -- Applications and effects of carbonic maceration / William D. Edinger -- Summer pruning of grapevines / Tony K. Wolf -- Activated carbon as a winemaking tool / Domenic Carisetti -- The principles and practices of cold sterile bottling / Chris Stamp --Monitoring insect and mite pests in Ohio vineyards 1984-86 / Steven R. Alm, Daniel M. Pavuk, and Roger N. William