A silicon doped hafnium oxide ferroelectric p–n–p–n SOI tunneling field–effect transistor with steep subthreshold slope and high switching state current ratio

Abstract

In this paper, a silicon–on–insulator (SOI) p–n–p–n tunneling field–effect transistor (TFET) with a silicon doped hafnium oxide (Si:HfO2) ferroelectric gate stack is proposed and investigated via 2D device simulation with a calibrated nonlocal band–to–band tunneling model. Utilization of Si:HfO2 instead of conventional perovskite ferroelectrics such as lead zirconium titanate (PbZrTiO3) and strontium bismuth tantalate (SrBi2Ta2O9) provides compatibility to the CMOS process as well as improved device scalability. By using Si:HfO2 ferroelectric gate stack, the applied gate voltage is effectively amplified that causes increased electric field at the tunneling junction and reduced tunneling barrier width. Compared with the conventional p–n–p–n SOI TFET, the on–state current and switching state current ratio are appreciably increased; and the average subthreshold slope (SS) is effectively reduced. The simulation results of Si:HfO2 ferroelectric p–n–p–n SOI TFET show significant improvement in transconductance (∼9.8X enhancement) at high overdrive voltage and average subthreshold slope (∼35% enhancement over nine decades of drain current) at room temperature, indicating that this device is a promising candidate to strengthen the performance of p–n–p–n and conventional TFET for a switching performance.

Improvement in ferroelectricity of HfxZr1−xO2thin films using ZrO2seed layer

“…erroelectric HfO 2 -based thin films are considered to be promising candidates for future memory device applications, such as ferroelectric random access memory (FeRAM), ferroelectric field-effect transistors (FeFET), tunnel field-effect transistors (TFET), and resistive random access memory (ReRAM). [1][2][3][4][5][6][7][8] It has been reported that HfO 2 -based thin films containing various dopants, such as Si, [9][10][11][12][13] Al, 14) Sr, 15) Y, [16][17][18][19] Sm, 20) Gd, [20][21][22] and La, 23) as well as undoped-HfO 2 films, [24][25][26] can exhibit ferroelectricity. Ferroelectric Hf x Zr 1−x O 2 (HZO) films are also obtained when the Hf : Zr ratio of the HZO film is 0:5 : 0:5, while HZO films with large proportions of Hf and Zr exhibit dielectric-and antiferroelectric-like behavior, respectively.…”

Enhanced Characteristics of Square-Shaped Extended Source TFET Via Silicon Carbide Polytype (3C-SiC) and a Dopant Pocket Layer

“…Furthermore, the Shockley-Read-Hall and Auger recombinations; concentration dependent mobility, bandgap narrowing effect, field dependent mobility and trap-assisted tunneling (TAT) models were used to model the recombination and generation in the highly doped regions. Also, we recently presented the validation of our simulation non-local BTBT model by tuning of the effective electron and hole masses as done in our earlier works 13,15,23,35,40 .…”

Surface potential–based analysis of ferroelectric dual material gate all around (FE‐DMGAA) TFETs

“…The channel length is 50 nm, which lies under tunneling gate and auxiliary gate of lengths 25 nm each. Employing Si:HfO 2 as a ferroelectric material due to its full compatibility with the standard CMOS process and enhanced scaling potential in nanometer range (5‐30 nm) . The dielectric constant of Si:HfO 2 is lower in comparison to its perovskite counterparts (PZT and SBT).…”

“…Employing Si:HfO 2 as a ferroelectric material due to its full compatibility with the standard CMOS process and enhanced scaling potential in nanometer range (5-30 nm). 29,30 The dielectric constant of Si:HfO 2 is lower in comparison to its perovskite counterparts (PZT and SBT). This property of Si:HfO 2 provides flexibility to be used in thin films which further reduces fringing effects.…”