P. Mialhe

Degradation of the diode ideality factor of silicon n–p junctions

Abstract An investigation of the effects of bulk and interface degradation processes on the junction ideality factor is presented. The ideality factor is extracted from a description of the simulated current–voltage characteristics of the junction, using a double exponential model. The junction ideality factor appears as a sensitive parameter appropriate to characterize the effect of recombination losses and to quantify the magnitude of junction devices degradation.

The thermodynamic compensation law

A demonstration of the thermodynamic compensation law is given; this law is shown to be a consequence of experimental approximations. It has been shown that the Meyer-Nelder rule is a consequence of experimental methods that consider a straight-line approximation of the In(X) versus 1/T plot of measurements of a physical quantity X in a limited temperature range. The ability of the Meyer-Neldel rule to give meaningful results is linked to the quality of the measurements and approximations made, but it appears that no genuine physical effect or fundamental relationships or universal quantities underlie its applicability.

On the aging of avalanche light emission from silicon junctions

The evolution of photon emission from the emitter-base junctions of bipolar transistors during electrical aging is monitored for the first time. Both electrical and optical characteristics are analyzed. Local variations of light emission intensity are observed for junctions biased at avalanche breakdown. During aging, regions of emission coalesce into small, bright regions; the total emission for the entire junction remains stable and relatively high. Changes in transistor current gain and breakdown voltage correlate with changes in light emission, and are consistent with a hydrogen migration model.

Switching times variation of power MOSFET devices after electrical stress.

The switching performance of three power MOSFET devices with different oxide thicknesses is studied after several periods of electrical stress. The thickest oxide reveals a large accumulation of positive charges in the oxide bulk after small periods of stress. These charges affect the switching parameters by increasing the rise time and by decreasing the fall time. Larger periods of stress reduce the effect of positive charges by increasing the number of interface states. The threshold voltage is decreased by the effect of a positive oxide charge and increases with the appearance of interface states. All these phenomena are less observable as we reduce the oxide thickness.

A NEW METHOD FOR THE EXTRACTION OF DIODE PARAMETERS USING A SINGLE EXPONENTIAL MODEL

A new method for extracting junction parameters of the single diode model is presented. A least squares method approach considers the deviation ∆V=f(I) between the experimental current-voltage (I-V) characteristic and a theoretical arbitrary characteristic. A specific case- the ∆V graph reducing to a straight line–is identified and the knowledge of the slope and of the intercept with the ordinate axis leads to the determination of the junction parameters. The method is applied to the characterization of the emitter-base junction of transistors and the results are discussed.

A junction characterization for microelectronic devices quality and reliability

Abstract With scaling down of devices for higher performance, ageing effects are becoming more important under standard working conditions. They have an important impact on the reliability of microelectronics devices since changes in the devices operating conditions due to lower power consumption are made. This work considers experimental degradations of the emitter–base characteristics in a transistor; the charge transport phenomena are related to structural properties and the evolution of standard operations, which introduce threshold voltage changes related to high injection effects. Both the junction ideality factor and the transient voltage appear as significant and sensitive parameters for quality and reliability characterization or hardness evaluation. A new reliability parameter RF is introduced and related to ageing of devices and to degradation processes.

Characterization method for ionizing radiation degradation in power MOSFETs

An innovative method for power MOSFETs characterization is presented. The radiation-induced degradation of structural parameters in the body-drain junction is shown to be related to the total dose. These results provide a new way, through these new parameters, to qualify the radiation response of power MOSFETs.

Recombination via radiation‐induced defects in field‐effect transistor

Modeling techniques of P‐N junctions have been applied for studying charge transport phenomena in metal‐oxide semiconductor field‐effect transistor structures. A parameter extraction method provides a precise description of the changes in conduction processes due to radiation damage in the integral body‐drain junction. A large increase of the space charge recombination current is related to band‐gap localized radiation‐induced defects.

Silicon oxide defects in aging of MOS electronic devices

Electrical ageing with applied drain and gate bias on n type metal-oxide-semiconductor (MOS) transistors has been shown to produce defects in the insulating oxide (SiO2) layer. The characterization method is based on numerical analysis performed on the substrate-drain junction experimental current-voltage curves to extract electrical parameters. The observed recombination carrier increase is related to hot carriers electron induced damage in the gate-to-drain overlap region.

Switching times variation of MOSFET devices with temperature and high-field stress

Switching times of power MOSFET devices are investigated as function of temperature and high-field stress. Measurements show that important variations are obtained on the devices turn-on time. The threshold voltage is decreasing with temperature and varies with stress, especially at low temperatures. The oxide leakage current is found to be having safe values even at high temperatures, stressing the devices does not increase the leakage current to unsafe values except for very high temperatures.