Design Considerations and Quantum Confinement Effect in Monolithic ε-Ge/InxGa1-xAs Nanoscale FinFETs Down to N5 Node (2022)

In this work, we have studied the effect of material parameters (indium (In) composition and doping), geometrical parameters [channel length <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${L}$ </tex-math></inline-formula> , fin width <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${W}$ </tex-math></inline-formula> , aspect ratio (AR)], and quantum confinement (QC) on the performance and operability of a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\varepsilon $ </tex-math></inline-formula> -Ge /InxGa <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{{1}-{x}}$ </tex-math></inline-formula> As hybrid CMOS system. In this system, the In compositional InxGa <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{{1}-{x}}$ </tex-math></inline-formula> As and tensile-strained Ge ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\varepsilon $ </tex-math></inline-formula> -Ge) grown on the InxGa <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{{1}-{x}}$ </tex-math></inline-formula> As layer were used as n- and p-channel FinFETs, respectively. The In composition in InxGa <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{{1}-{x}}$ </tex-math></inline-formula> As layer (lattice matched with graded InxAl <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{{1}-{x}}$ </tex-math></inline-formula> As buffer) determines the amount of tensile strain in Ge. This hybrid system utilizes the benefits of metamorphic (InxGa <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{{1}-{x}}$ </tex-math></inline-formula> As/InxAl <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{{1}-{x}}$ </tex-math></inline-formula> As) as well as pseudomorphic ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\varepsilon $ </tex-math></inline-formula> -Ge/InxGa <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{{1}-{x}}$ </tex-math></inline-formula> As) heteroepitaxy to create high-performance tunable complementary devices, suitable for 0.5 V CMOS operation. The device metrics such as, threshold voltage, ON-current ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{\text {on}}$ </tex-math></inline-formula> ), OFF-current ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{\text {off}}$ </tex-math></inline-formula> ), subthreshold-swing (SS), and drain-induced barrier lowering (DIBL), and their dependence on material and geometrical parameters were evaluated using self-consistent analytical solvers scaled down to the N5 node. At these scaled dimensions, this hybrid system demonstrated ultralow leakage current and SS for the n-FinFET and p-FinFET of 10 pA/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> , 27 nA/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> , 85, and 95 mV/dec, respectively. With the effect of QC, we identify a transition fin width ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${W}_{T}$ </tex-math></inline-formula> ) associated with scaling of alternate channel FinFETs, at which the performance is optimum and below <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${W}_{T}$ </tex-math></inline-formula> , the benefits of scaling are diminished. Moreover, this hybrid system has a potential to find applications in optoelectronic and RF systems as well as high-performance computing.