D. Pantić

Charge-pumping characterization of SiO/sub 2//Si interface in virgin and irradiated power VDMOSFETs

The applicability of charge-pumping technique to characterize the oxide/silicon interface in standard power Vertical Double-diffused (VD)MOS transistors is studied. Qualitative analysis of the charge-pumping threshold and flat-band voltage distributions in the VDMOS structure, supported with rigorous transient numerical modeling of the charge-pumping effect, shows that the measurements can be carried out in the subthreshold region. This conclusion is confirmed by various experimental results. The characteristics, i.e. charge-pumping current versus gate top level, is studied in detail. The changes in the characteristics after /spl gamma/-ray irradiation are analyzed. A charge-pumping-based method for separate extraction of interface state density and density of charge trapped in the oxide after irradiation of VDMOSFETs is proposed. The validity and limitations of the method are studied by experiments and modeling.

3D simulation of cross-shaped Hall sensor and its equivalent circuit model

The complete technology process flow and electrical characteristics of cross-shaped Hall sensor in high voltage bulk CMOS technology have been accurately simulated in 2D and 3D using ISE TCAD system. Consistent 3D doping profile is obtained by interpolation, exchanging data between several 2D doping profiles. In order to facilitate the analysis of an electrical circuit incorporating a Hall sensor, an appropriate equivalent circuit model of cross-shaped Hall sensor with voltage control non-linear resistors is suggested. Finally, the results acquired by 3D electrical characteristic simulations using ISE tool DESSIS and equivalent-circuit analyses using program SPICE are compared.

The application of charge-pumping technique to characterize the Si/SiO 2 interface in power VDMOSFETs

Abstract The possibility to perform charge-pumping measurements on power VDMOS transistors is investigated. By analyzing the spatial distributions of the charge-pumping threshold and flat-band voltages it is concluded that the charge-pumping measurements can be carried out in the subthreshold region of the device. This conclusion is confirmed by two-dimensional transient numerical modeling of the charge-pumping effect and supported by experiments. The method for a separate extraction of interface state and fixed charge densities generated by irradiation in the oxide of VDMOSFETs is proposed.

Process design and optimization of the channel doping profile in power VDMOSFETs

In this paper the procedure for the process design of the channel doping profile in low-voltage power VDMOSFETs is presented. An optimization of some of the process parameters having greatest influence on the shape of the channel doping profile is briefly described. Effects of the variation of the p-body diffusion time on the threshold voltage and channel length are discussed in particular. It is shown that the threshold voltage sensitivity due to variations of p-body diffusion time can be minimized by appropriate adjustment of the source diffusion in the lateral direction. The results obtained show qualitatively good agreement of the two-dimensional process and device simulation with the design rules.

Dynamic MAGFET model for sensor simulations

A new model for a magnetic-sensitive split-drain MOSFET (MAGFET) consisting of only two n-channel MOS transistors (NMOSTs) in the equivalent sub-circuit is described. The model developed is based on the non-quasi-static MOST model of a conventional NMOST, modified to include the effects of the Lorentz force. On the basis of the results of three-dimensional numerical device simulations, it is shown that the new model can accurately predict the absolute and the relative MAGFET sensitivity for a wide range of the device biasing conditions. Unlike previous models, the new MAGFET model can also predict device dynamic response to time-varying magnetic fields more realistically.

A new technology computer-aided design (TCAD) system based on neural network models

A new technology computer-aided design (TCAD) system based on neural network models is proposed and efficiency is demonstrated through the simulation and optimization of power VDMOSFET manufacturing technology.

Inverse modeling of semiconductor manufacturing processes by neural networks

This paper presents the most important aspects of semiconductor processes modeling and a process/device optimization technique based on neural network models. Efficiency of adaptive neural networks in complex process modeling and inverse modeling is demonstrated through modeling of ion implantation process. Also, efficiency of Technology Computer-Aided Design (TCAD) system containing direct and inverse neural network models is demonstrated through optimization of complex manufacturing process flow of low voltage power VDMOSFET. Results of optimization obtained by using direct and inverse neural network models are compared with those obtained by using world-known process simulator MUSIC 2 and modified version of device simulator MINIMOS 6, and an excellent agreement is achieved. It is shown that incorporation of neural network models in TCAD systems significantly improves optimization technique, thus leading to significant reduction of computational time.

The efficient simulation of point defects diffusion by an adaptive multigrid method

The central goal of this paper is to demonstrate the efficiency of adaptive multilevel numerical method based on full multigrid algorithm for the simulation of point defects diffusion. This numerical approach is implemented in process simulator MUSIC [1] and it is applied for the simulation of interstitials and vacancies diffusion during the local oxidation process.

A new multi-layer ion implantation model for process simulation☆

Abstract A new model for calculation of ion implantation impurity profiles in general multi-layer targets is presented. The model is based on a transformed and scaled Maxwell energy distribution function as well as on the electronic/nuclear stopping power theory. The concentration profiles of arsenic and boron ions implanted through oxide and nitride layers on silicon substrate have been calculated and compared with the experimental data.

Educational software for power VDMOS transistors

This paper describes educational software for power VDMOS transistors used at the University of Nis, Faculty of Electronic Engineering, Yugoslavia. It is intended to serve the education of both undergraduate and postgraduate students. The software is designed to support process and device simulation, experimental device characterization and optimization of the technology. Its architecture is described in detail, and educative simulation examples are also provided.