Power Characteristics of Selective Buried Oxide MOSFET

Abstract

Power dissipation is an important factor in electronic circuit design due to the decreasing feature size of microelectronic devices, high clock frequencies, and large die size, as well as the growing number of mobile, battery-operated systems. The aim of low-power design for battery-powered devices is thus to increase battery service life while meeting performance requirements. Reducing power dissipation is a design goal for portable and non-portable devices since extreme power dissipation results in increased packaging and cooling costs as well as potential reliability problems. Recently, Silicon On Insulator (SOI) devices have been used that exhibit vertical and horizontal isolation of active devices from the substrate, which leads to higher speed operation and low leakage current. However, SOI devices have serious drawbacks such as the kink effect and self-heating. In this thesis, a new Metal-Oxide Semiconductor Field-Effect-Transistor (MOSFET) structure design is introduced to eliminate the kink effect and self-heating, and to reduce power dissipation while still keeping in consideration the advantages of others such as Bulk and SOI MOSFETs. The new structure is called SELective Buried OXide MOSFET (SELBOX). This transistor combines the advantages of the Bulk and SOI while eliminating the drawbacks. This thesis reviews the various power dissipation reduction methods available in the literature. Next it proposes the structures of Bulk, SOI, and SELBOX for NMOS, PMOS, and CMOS over the first stage followed by a simulation to obtain current-voltage characteristics and static power dissipation. The various MOSFET structures are evaluated in terms of power dissipation. Simulation results will show that the static power dissipation of the Bulk MOS as a single transistor is less than others due to the slow increase in the drain current. Also, SELBOX behavior is very close to Bulk with the advantages of SOI. Simulation results of the CMOS devices show that the static power dissipation of Bulk MOS is very high due to well leakage. SOI has the lowest power dissipation and SELBOX is very close to it. In all cases, SELBOX structure succeeded in reducing power dissipation with a high operating speed, elimination of self-heating, and without a kink effect.