Eric Joubert

Achieving of an optical very high frequency modulated wave source using heterodyne technique

We describe a method for generating an amplitude modulated optical wave in the range of the telecommunication frequencies. The originality is to guaranty a tunability of the source up to 275 GHz with about 45 MHz spectral width. The principle is based on the optical heterodyne of two DFB laser sources emitting around 1550 nm. After describing various existing methods for optical wave modulation and for millimetric signal generation, we concentrate our interest on the heterodyne technique. We carry out a study concerning the spectral width influence on the spectral purity of the generated signal. Then, the experimental measurement set-up is described, as well as characterization of the spectral width of the lasers. Finally, we present the results obtained in reception of the beat of two identical lasers on a 25 GHz bandwidth photodiode.

Characterization of ESD stress effects on SiC MOSFETs using photon emission spectral signatures

This article presents a robustness study of SiC power MOSFETs to Electrostatic Discharge (ESD), by photon emission (PE) and spectral PE techniques (SPE). Investigations in different polarization modes are performed in photoemission PE, and a linear dependence in gate voltage has been identified. A decrease in the intensity of the ESD degraded device emissions has been noticed. A SPE system has been developed, and PE spectrum has been extracted for both fresh and degraded devices. SPE analyses are reported and correlated with electrical analyses to localize and identify the failure. The ESD degradation is seems to be related to a pn junction degradation. C-V analyses are conducted to prove this hypothesis.

Generation of an amplitude modulated optical wave up to 275 GHz by laser wave mixing for optical component bandwidth measurement

This paper presents a method to achieve an amplitude-modulated optical wave in the range of telecommunication frequencies for optical components bandwidth tests. The principle is based on the optical heterodyning of two free distributed feedback lasers. The frequency tunabil- ity of the modulated wave reaches 275 GHz with high stability. These characteristics constitute the originality of our work. Our laboratory has developed an experimental fusion setup that enables the realization of numerous optical fiber components. Component bandwidth measurement enables their validation for high-rate data transmissions. We present in this paper results obtained for a 57-GHz beat signal in a fast photodiode and we describe bandwidth optical components tests in the 0 to 40 GHz range.

Simultaneous measures of temperature and expansion on electronic compound

In this paper is presented a new approach for measuring physical values of micro-electronic compounds. Indeed an optical system is used to quantify simultaneously surface temperature and expansion of a component. This is done with a Michelson interferometer. To compare the method, the measured temperature was correlated with two other methods, IR camera and ESD diode.

New approach for thermal investigation of a III – V power transistor

In this paper is presented a new method for characterisation of temperature of AlGaN-GaN transistor. An ellipsometer is also explained for measure of refractive index and so propagation time constant.

5 – Reliability and Qualification Tests for High-Power MOSFET Transistors

Abstract: Silicon (Si) and silicon carbide (SiC) MOSFET transistors have multiple weak points, resulting in multiple failure modes and mechanisms. To study the reliability of these transistors using the non-destructive technique described in Chapter 8, the application of an accelerated aging process to these components is essential. This chapter begins by describing the various failure mechanisms of Si and SiC MOSFETs. To allow the most suitable aging test in terms of simplicity and speed to be chosen, this chapter then focuses on the reliability and qualification tests applied by manufacturers. Finally, we present the results of accelerated qualification tests applied to Si and SiC MOSFET transistors. These components are analyzed using the technique of photoemission microscopy.

Reliability Study of High-Power Mechatronic Components by Spectral Photoemission Microscopy

Abstract: Spectral photoemission microscopy is a semidestructive method of failure analysis that aims to locate defects and identify failure modes. Previous generations of equipment used for this type of analysis, such as spectrometers, filters, or prisms, had inherent limitations. In this chapter, we present a spectral photoemission system that allows the photoemission spectra to be rapidly derived by means of a diffraction grating placed in the optical path of a photoemission microscope. Using the information obtained from this system, we can identify a spectral signature that is specific to each defect and that can be correlated with each failure mechanism. The method of calibration of this system is presented and the results obtained with different transistor technologies are compared.

Characterization of HTRB stress effects on SiC MOSFETs using photon emission spectral signatures

This article presents a robustness study of SiC power MOSFETs to Electrostatic Discharge (ESD), by photon emission (PE) and spectral PE techniques (SPE). Investigations in different polarization modes are performed in photoemission PE, and a linear dependence in gate voltage has been identified. A decrease in the intensity of the ESD degraded device emissions has been noticed. A SPE system has been developed, and PE spectrum has been extracted for both fresh and degraded devices. SPE analyses are reported and correlated with electrical analyses to localize and identify the failure. The ESD degradation is seems to be related to a pn junction degradation. C-V analyses are conducted to prove this hypothesis.

Internal Temperature Measurement of Electronic Components

This chapter presents the results of a study in which the temperature and the microdisplacements of the chip surface of high-frequency power electronic components used in radar and telecommunication systems are measured. Several techniques are applied. Their advantages, disadvantages and shared fields of application are discussed. Results from several samples show that the different approaches converge. The originality of this study is that the measurements of chip surface temperature and displacement are obtained simultaneously. This approach makes it possible to then calculate the thermal resistance of an electronic component and characterize the evolution of this resistance over component lifetime.

A workbench development for L-band LDMOS amplifier reliability study (electronic power transistors reliabilty for radar applications)

This paper describes the conception and making of an ageing workbench for power microwave transistors. This bench has the particularity to address high power components reaching one KW pulse operating, over the L-band with in-situ electrical measurements process. Considering three kinds of stresses, we present results regarding the performance and reversible damage of a commercial silicon transistor technology for radar applications.