Investigation of barrier height distributions over the gate area of Al-SiO2-Si structures, Journal of Telecommunications and Information Technology, 2007, nr 3

Distributions of the gate-dielectric EBG(x, y) and semiconductor-dielectric EBS(x, y) barrier height values have been determined using the photoelectric measurement method. Modified Powell-Berglund method was used to measure barrier height values. Modification of this method consisted in using a focused UV light beam of a small diameter d =0.3 mm. It was found that the EBG(x, y) distribution has a characteristic dome-like shape which corresponds with the independently determined shape of the effective contact potential difference fMS(x, y) distribution. On the other hand, the EBS(x, y) distribution is of a random character. It is shown that the EBG(x, y) distribution determines the shape of the fMS(x, y) distribution. The model of the EBG and EBS barrier height distributions over the gate area has been proposed

LPT and SLPT Measurement Methods of Flat-Band Voltage (VFB) in MOS Devices, Journal of Telecommunications and Information Technology, 2009, nr 4

The photoelectric techniques are often used for the measurements of metal oxide semiconductor (MOS) structure parameters. These methods, which consist in illuminating the MOS structure with a semitransparent metal gate by a UV light beam, are often competitive for typical electric measurements. The results obtained by different photoelectric methods are, in many cases, more accurate and reproducible than the results of other measurements. The flat-band voltage VFB is an important parameter of any MOS structure since its value influences the threshold voltage VT , which decides for example about power consumption of MOS transistors. One of the methods to measure the VFB value is the electric method of C(V) characteristic. This method involves certain calculations and requires the knowledge about parameters of the investigated sample. The accuracy of this method is rarely better than ±100 mV (for higher doping of the substrates the accuracy is worse). The other method of VFB value determination, outlined in this article, is the photoelectric light pulse technique (LPT) method. This method based on the idea proposed by Yun is currently being optimized and verified experimentally

Energy concepts involved in MOS characterization, Journal of Telecommunications and Information Technology, 2007, nr 2

Starting from a quantum statistical reasoning, it is demonstrated that entropy properties of silicon/silicon dioxide interface electron traps may have a strong influence on measured distributions of interface states, depending on measurement method used. For methods, where the Fermi-level is used as a probe to define an energy position, the scale is based on free energy. On the other hand, methods based on thermal activation of electrons give the distribution on an enthalpy scale. It is shown that measured interface state distributions are influenced by the distribution of entropy, and that common features of measured energy distributions may be influenced by entropy variations. These results are used to interpret experimental data on the energy distribution of electron capture cross sections with an exponential increase followed by a more or less constant value as the energy distance of the traps from the conduction band edge increases. Such a relation is shown to be consistent with a situation where the emission and capture processes of electrons obey the Meyer-Neldel rule

Comparison of the barrier height measurements by the Powell method with the ΦMS measurement results, Journal of Telecommunications and Information Technology, 2005, nr 1

n this work, we have compared the barrier height measurements carried out using the Powell method with the photoelectric effective contact potential difference (&phiMS) measurement results. The photoelectric measurements were performed on the samples that were previously applied in the investigation of the influence of stress on the duration of annealing in nitrogen. This paper shows that the results of barrier height measurement using the Powell method differ significantly from the &phi(MS) measurement results

Effects of stress annealing on the electrical and the optical properties of MOS devices, Journal of Telecommunications and Information Technology, 2005, nr 1

In this paper we show the results of a study of the effects of high-temperature stress annealing in nitrogen on the refraction index of SiO2 layers and electrical properties in metal-oxide-semiconductor (MOS) devices. We have experimentally characterized the dependence of the reduced effective contact potential difference (ECPD), the effective oxide charge density (Neff), and the mid-gap interface trap density (Dit) on the annealing conditions. Subsequently, we have correlated such properties with the dependence of the refraction index and oxide stress on the annealing conditions and silicon dioxide thickness. Also, the dependence of mechanical stress in the Si-SiO2 system on the oxidation and annealing conditions has been experimentally determined. We consider the contributions of the thermal-relaxation and nitrogen incorporation processes in determining changes in the SiO2 layer refractive index and the electrical properties with annealing time. This description is consistent with other annealing studies carried out in argon, where only the thermal relaxation process is present

Variability of the local ΦMS values over the gate area of MOS devices, Journal of Telecommunications and Information Technology, 2005, nr 1

The local value distributions of the effective contact potential difference (ECPD or the øMS factor) over thegate area of Al-SiO2-Si structures were investigated for thefirst time. A modification of the photoelectric øMS measurement method was developed, which allows determination of local values of this parameter in different parts of metaloxide-semiconductor (MOS) structures. It was found that the øMS distribution was such, that its values were highest far away from the gate edge regions (e.g., in the middle of a square gate), lower in the vicinity of gate edges and still lower in the vicinity of gate corners. These results were confirmed by several independent photoelectric and electrical measurement methods. A model is proposed of this distribution in which the experimentally determined øMS(x; y) distributions, found previously, are attributed to mechanical stress distributions in MOS structures. Model equations are derived and used to calculate øMS(x; y) distributions for various structures. Results of these calculations remain in agreement with experimentally obtained distributions. Comparison of various characteristics calculated using the model with the results of photoelectric and electrical measurements of a wide range of Al-SiO2-Si structures support the validity of the model

Influence of nitrogen implantation on electrical properties of Al/SiO2/4H-SiC MOS structure

abstractEN: An influence of nitrogen implantation dose on the properties of MOS structure is analyzed. The properties are investigated using C-V, I-V measurements, Raman spectroscopy, and XPS profiling. It has been shown that the trap density is derectly related to implantation damage and conditions.score: 5collation: 733-73