Variation of source gate workfunction on the performance of dual material gate rectangular recessed channel SOI‐MOSFET

Abstract

This paper attempts to propose a new device as workfunction modulated dual metal rectangular recessed channel silicon on insulator (WMDMRRC-SOI) MOSFET. This model takes the advantage of recessed channel to reduce the hot-carrier effect and a linear variation of workfunction at source side metal gate to achieve improved threshold voltage and electron transportation efficiency. The characteristics of WMDMRRC-SOI MOSFET are analyzed in terms of electron behaviour like mobility, temperature, and velocity in the channel region. The impact of negative junction depth on threshold voltage and short-channel effects like drain induced barrier lowering, subthreshold slope are analyzed to optimize the characteristics of the proposed architecture.Performance parameters of WMDMRRC-SOI MOSFET are compared with the results of DMRRC-SOI MOSFET and conventional RRC-SOI MOSFET.The comparison interprets that with higher intrinsic gain and lower distortion, the proposed architecture gives better analog performance and enhanced short channel parameters. The results obtained are validated through Sentaurus TCAD device simulator. KEYWORDSnegative junction depth (NJD), recessed channel (RC), short-channel effects, silicon-on-insulator (SOI) | INTRODUCTIONScaling of MOS dimensions is essential in order to realize a high-speed and higher-packing density MOS integrated circuit, which results in high power consumption. Attempts to reduce power consumption lead to the degradation of MOSFET carrier transport efficiency. With aggressive technology scaling, the improvement in device reliability has been the prime focus in scaled MOSFET. Thus, performance enhancement can be achieved by overcoming the undesirable short-channel effects. [1][2][3] These barriers can be overcome by silicon-on-insulator (SOI) technology, which is implemented by assimilating an oxide layer on silicon body giving a perfect isolation to avoid latch up in conventional MOS structure. MOSFET along with SOI technology is popular for high temperature applications, as it provides lower leakage current at source/drain junction. Due to its better radiation tolerance, it is also useful for space applications. Above all, the steeper subthreshold characteristics make this device suitable for faster switching circuit applications. Although SOI technology is widely used, still some problems like gate transport inefficiency persists. 4-11

Gate electrode stacked source/drain SON trench MOSFET for biosensing application

“…Again the threshold voltage is termed as the minimum voltage required to make device turn on. This is calculated by the value of gate voltage V gs for which minimum surface potential equals to the twice of Fermi potential [35,57]. Drain current varies with applied gate voltage at constant drain to source voltage V .…”

“…A dual metal (DM) gate with a nano-cavity length (l nc ) of 8 nm, oxide-thickness (t ox ) of 2 nm, and gate length (L G ) of 20 nm is implemented in the proposed biosensor [23]. As the implementaion of higher gate workfunction near to the source end offers an improve sensitivity for which the metal workfunction of M1 = 4.7 eV, and M2 = 4.1 eV are being considered in the gate region [35,37]. Again the specification of the stack source/drain formed by silicon and germanium material is taken as reported in [40].…”

“…However, the transport efficiency of the recessed channel (RC) MOS deteriorates due to the presence of the groove corner which affects the device threshold voltage. Therefore with the help of workfunction engineering and stack source/drain, the channel field can be improved to boost the carrier transport efficiency that may give better sensitivity for biosensors [34][35][36][37]. Now a days, the silicon-on-insulator (SOI) technique provides a better isolation between channel and body to enhance the device SCEs.…”

Improved post-radiation behavior of FinFET based CMOS with workfunction modulated gate

“…Moreover, gate workfuction of the device is directly proportional to threshold voltage. The threshold voltage of MGW device is more as compared to the SGW device and high V th devices are mostly preferable for space applications [15,21,[30][31][32][42][43][44][45][46][47].…”