Channel Length Scaling Pattern for Cylindrical Surrounding Double-Gate (CSDG) MOSFET

Maduagwu Anthony Uchechukwu,Viranjay M. Srivastava

doi:10.1109/access.2020.3006705

Abstract

The natural length of MOSFETs helps to describe the potential distribution in the Silicon substrate. This natural length varies in different device structures, from a single gate to multi-gate device geometry. To measure the short channel effects degree, the natural length should be known because various vital parameters such as OFF-current, Roll-off threshold voltage, and drain induced barrier lowering depend on it. In this research work, authors have presented a scaling theory for Cylindrical Surrounding Double-Gate (CSDG) MOSFET, which guide the device design. The scaling method has been derived, based on the application of the Poisson equation, in a cylindrical structure using Parabolic Potential Approximation (PPA) along the radial direction (substrate part only). Furthermore, a comparison with cylindrical surrounding-gate MOSFETs, Silicon-on-insulator, and double-gate device geometries has been obtained. The results obtained using the PPA model show that CSDG MOSFET has the least natural length, making it a better component for SCEs immunity.

Highlights

The MOSFETs scaling is the driving force for the recent developments in the semiconductor industry [1]–[3]
The natural scaling of Cylindrical Surrounding Double-Gate (CSDG) MOSFET, threshold voltage variations, and DRAIN INDUCED BARRIER LOWERING (DIBL) behavior are obtained with Eq (5) to Eq (24)
ASPECTS In this research work, a natural scaling length characterization has been derived for the design of CSDG MOSFETs to access its scaling potential based on the internal and external gates

Summary

INTRODUCTION

The MOSFETs scaling is the driving force for the recent developments in the semiconductor industry [1]–[3]. The derived natural length of close form-expression will enable the device engineers to estimate the maximum allowable Silicon thickness to avoid short channel effects in CSDG MOSFET via the scaling factor. In this present research work, the natural lengths of the CSDG MOSFET have been developed using a 2-D Poisson equation based on the PPA model [21]. MATHEMATICAL MODELLING OF THE NATURAL LENGTH FOR CSDG MOSFET The Poisson equations have been solved, based on the boundary conditions from Fig. 3, to obtain its natural length for both internal and external gates. Proper care must be taken in choosing the values of ‘b’ in designing the device structure

EFFECTS OF THE NATURAL LENGTH ON THE SHORT CHANNEL BEHAVIOUR OF CSDG MOSFET

RESULTS AND ANALYSIS

CONCLUSIONS AND FUTURE ASPECTS