P₂S₅/(NH₄)₂S_{<italic>x</italic>}-Based Sulfur Monolayer Doping for Source/Drain Extensions in n-Channel InGaAs FETs

Abstract

Ultrashallow junctions that are abrupt and have low resistance are needed for the source/drain extensions (SDEs) of MOSFETs at future technology nodes. In addition, the use of 3-D devices, such as FinFETs or nanowire FETs, will require a doping process that is conformal. In this paper, we discuss P 2 S 5 /(NH 4 ) 2 S x -based doping for potential use in the formation of SDEs for n-channel InGaAs FETs. MOSFETs with source and drain formed using this doping technique are demonstrated. The effect of the dopant activation step on device performance is also studied.Index Terms-InGaAs, monolayer doping (MLD), (NH 4 ) 2 S x , P 2 S 5 , source-drain extensions (SDEs).

Understanding Thermal Evolution and Monolayer Doping of Sulfur-Passivated GaAs(100)

“…As for the case of analogous Si MLD processes, this method has been successfully demonstrated in several systems, including InP nanostructures, InAs, and InGaAs. [15][16][17]23,24 However, there is no mechanistic understanding of the thermal evolution of S atoms and nature of intermediate structures. Moreover, the need for capping layers is not well established.…”

Liquid-Phase Monolayer Doping of InGaAs with Si-, S-, and Sn-Containing Organic Molecular Layers

“…Solution-phase S doping of InGaAs has been relatively widely reported due to the simplicity of the procedure. 36−39 Ammonium sulfide is often used to remove the native oxides on InGaAs, but the process conveniently results in a S-terminated surface, allowing diffusion of S as a monolayer into the InGaAs surface via a rapid thermal anneal step. Although not a traditional MLD process, due to the gas-phase nature of the dopant precursor and high-vacuum requirements of the deposition process, Kong and co-workers recently reported the Si MLD of InGaAs nanostructures by means of a MOCVD-deposited silane layer with a thickness of a few monolayers.…”

“…There have been reports of direct bonding to oxide-free III–V surfaces using organic thiols, − and due to the simplicity of the procedure and availability of suitable commercial molecules, as well as the excellent oxidation resistance offered by III–V-thiol chemistry, this was one of the functionalization approaches used in this study. Solution-phase S doping of InGaAs has been relatively widely reported due to the simplicity of the procedure. − Ammonium sulfide is often used to remove the native oxides on InGaAs, but the process conveniently results in a S-terminated surface, allowing diffusion of S as a monolayer into the InGaAs surface via a rapid thermal anneal step. Although not a traditional MLD process, due to the gas-phase nature of the dopant precursor and high-vacuum requirements of the deposition process, Kong and co-workers recently reported the Si MLD of InGaAs nanostructures by means of a MOCVD-deposited silane layer with a thickness of a few monolayers .…”