Compact Modeling

An explicit solution for long-channel surrounding-gate (SRG) MOSFETs is presented from intrinsic to heavily doped body including the effects of interface traps and quantum effects. The solution is based on the core SRGMOSFETs model of Unified Charge Control Model (UCCM) for heavily doped condition. The UCCM model of highly doped SRGMOSFETs is derived to obtain the exact equivalent expression as in undoped case. Taking the advantage of the undoped explicit charge-based expression, the asymptotic limits for below threshold and above threshold have been redefined to include the effect of trap states for heavily doped case. After solving the asymptotic limits, an explicit mobile charge expression is obtained which include the trap state effects. The explicit mobile charge model shows very good agreement with respect to numerical simulation over practical terminal voltages, doping concentration, geometry effects, and trap state effects due to the fixed oxide charges and interface traps. Then, the drain current is obtained using the Pao–Sah's dual integral, which is expressed as a function of inversion charge densities at the source/drain ends. The drain current agreed well with implicit solution and numerical simulation for all regions of operation without employing any empirical parameters. In addition, the quantum effects are included based on quantum corrected model. The threshold voltage shift due to quantum confinement is incorporated to the classical model and the effective gate capacitance is recalculated due to series connected quantum capacitance. Comparison with previous explicit model has been conducted to verify the competency of the proposed model with doping concentration of 1 × 10 19 cm −3 as the proposed model has better advantages in terms of its simplicity and accuracy at higher doping concentration.

Modeling and simulation of the behavior of a system consisting of many single devices is an essential requirement for the reduction of design cycles in the development of microsystem applications. Analytic solutions for the describing partial differential equations of each component are only available for simple geometries. For complex geometries, either approximations or numerical methods can be used. However, the numerical treatment of the PDEs of thousands of interconnected single devices with each exhibiting a complex behavior is almost impossible without reduction of the order of unknowns to a lower-dimensional system. We present a fully automatic method to generate a compact model of second-order linear systems based on the Arnoldi process, and provide an example of successfull model order reduction to a gyroscope. Thus, the engineers need to simulate the system as a whole. By experience, they are able to define coupling effects between devices, which can be probed at certain ...

This paper present a design of a Frequency Selective Surface (FSS) to improve gain and efficiency of a microstrip patch antenna operating in X-band at 10 GHz. The band-stop frequency selective surface (FSS) designed at the operating frequency of the antenna is used. FSS structure is configured as a superstrate for the microstrip patch antenna. The main goal of this paper is design a compact microstrip antenna module (microstrip patch and FSS structure). Simulation results using CST studio showed that high gain (54 % increment) and efficiency is increased to 97% have been achieved by the proposed antenna module (MS and FSS). The equivalent circuit of proposed FSS unit cell in ADS software has been evaluated and compared to simulation results (CST studio) to improve characteristics of the antenna. The proposed antenna module is extremely compact high gain and it can be used for X-band applications.