A. Rusu

Buried field rings - a novel edge termination method for 4H-SiC high voltage devices

This paper is concerned with a numerical study of a novel edge breakdown termination technique for 4H-SiC high voltage devices. Buried field rings (BFRs) are proposed to be used, for the first time, in SiC devices as an effective termination method and the concept is numerically demonstrated for 4H-SiC MESA JFET structures. By using 4 BFRs for a MESA JFET, a breakdown voltage of 1,590 V has been achieved, representing more than 90% of the ideal bulk breakdown value (1,750 V). The influence of the buried rings doping on the blocking mode behaviour and the effect of the SiC/SiO/sub 2/ interface charge on the breakdown voltage are studied. It is evidenced that the BFR termination offers a very stable blocking mode behaviour and the influence of processing conditions on its over-all performance is negligible. For comparison, some results for guard rings and junction termination extension are also presented.

From Ψ-MOSFET with silicon on oxide to Ψ-MOSFET with silicon carbide on nitride

The Ψ-MOSFET is a device used in SOI electrical characterization. The aim of this paper was to establish a comparison between these transistors made in four variants: (1) with silicon film on buried oxide; (2) with silicon carbide film on buried oxide; (3) with silicon film on buried nitride; and (4) with silicon carbide film on buried nitride. ATLAS software simulated these structures. Besides this virtual experiment, a more complex model for the flat-band voltage is provided.

Alternative methods of parameters extraction based on the Pseudo-MOS technique

The pseudo-MOS transistor is a dedicated device for in situ electrical characterization of the SOI wafers. In this paper were extracted some parameters for a 200nm Si-film manufactured in SIMOX technique. In this scope, experimental Curves I/sub D/-V/sub G/, I/sub D/-V/sub D/ in inversion and accumulation were used, This work presents an alternative method for the threshold and fiat-band voltages extraction, using the Non-linear Electrical Conduction Theorem.

Theoretical and numerical investigation of SiC JFET and MOSFET at 6.5 kV

This paper presents a preliminary theoretical and numerical investigation of 4H-SiC JFET and MOSFET at 6.5 kV. To improve the on-state/breakdown performance of the JFET, buried layers in conjunction with a highly doped buffer layer have been used. Trench technology has been employed for the MOSFET. The devices were simulated and optimized using the MEDICI simulator. From a comparison between the two devices, it turns out that the JFET offers a better on-state/breakdown trade-off, while the trench MOSFET has the advantage of MOS-control.

The influence of buried insulator type and film thickness on threshold voltage of a partially and fully depleted SOI-MOSFET

Nowadays SOI technologies represent a milestone in the fabrication of devices and integrated systems on thin films. The analytical models for the threshold voltage are useful for many SOI devices. Our analysis has focused on partially and fully depleted films, achieved on insulators like oxide, nitride or oxinitride. This paper gives a simple and accurate estimation of the threshold voltage. The results were in a good agreement both with PISCES numerical simulations and with experimental data.

Gated diode in breakdown voltage collapse regime — A test vehicle for oxide characterization

A new method for oxide characterization, based on flat-band voltage shift direct measurement is presented. This opportunity appears in the breakdown voltage collapse, for a gated diode operated in the common-cathode configuration. Additionally, the proposed method outfits uniform conditions for voltage drop across the oxide and carrier multiplication.

Analysis of the non-linear responses of some biosensors

This paper is focused on biosensors that comprise a non-linear transducer element (ISFET, MOSFET). These active components give a non-linear dependence of the outputs characteristics versus input stimulus. Some experimental responses of two biosensors, reported in specialty literature, were investigated with the Non-Linear Electrical Conduction Theorem (NECT).

Modeling the suspended gate MOSFET used as voltage programmable switch

This paper is a new approach to investigate and model the behaviour of the SGMOSFET with an external force applied on the mobile gate. Mechanical influences on the device threshold voltage V/sub T/ are presented together with the advantages and the limitations of this operating regime of the SGMOSFET.

MOSFET mobility degradation modelling

The design of linear analog circuits lacks models for state-of-the-art MOS transistors to accurately describe distortion effects. This is mainly due to inaccurate modelling of the mobility degradation effect i.e. the dependence of carrier mobility in the inversion layer on the normal electric (gate) field. A new mobility relation in agreement with experiment was obtained using quantum mechanical transport analysis.

Image force effect on forward characteristic of a rectifier metal-semiconductor contact

The image force effect is appreciated, especially, for the reverse regime of the rectifier metal-semiconductor contact, causing a weak dependence of the saturation current on the applied voltage. Applying this concept to the forward bias, at high values of currents, the ideality factor has an important increase. Combining this effect with the effect of the series resistance, which is important in the same range of currents, an important depreciation of the rectifier properties is observed.