Key parameters for achieving n-type conformal doping desirable for source/drain extension regions of Si n-channel fin field effect transistors (FinFETs) have been determined for self-regulatory plasma doping using an AsH3 plasma diluted with He. Two-dimensional scanning spreading resistance microscopy revealed that this technique is advantageous for conformal doping of fin structures. An excellent resistivity conformality was obtained with the ratio of the resistivity of fin sidewall to that of the fin top surface being 0.85. A high total gas flow rate and a high AsH3 concentration were found to be important conditions for realizing conformal doping. The results revealed that a short gas residence time and high molar concentrations of AsH3 and He in the process chamber are essential physical parameters for realizing large amounts of dopant species with finite decomposition times. When these conditions are realized, a sufficiently large amount of As is supplied to both the top surface and the sidewall so that the lowest resistivity is uniformly obtained in these regions because the activated As concentration is saturated even when excess As is supplied to the fin surfaces. The trade-off that exists between conformal doping and fin erosion is discussed. This technique will be useful for realizing conformal doping for the extension regions of n-channel FinFETs for the 22 nm node and beyond.

A new Self-Regulatory Plasma Doping (SRPD) technique with B 2 H 6 /Helium gas plasma has been successfully developed that provide conformal doping for fins and precise controllable ultra-shallow doping for planar FET. Manufacturing level of process controllability (<1% on dose) of the new SRPD has been realized, and advantage of the SRPD has been verified with FinFETs with metal/high-k gate stack and planar pMOSFETs for the first time. Short channel effect (SCE) improvement for FinFETs is clearly obtained. Dramatically I on enhancement (+14% I on at the I off of 10 -8 A/um vs. ion implant ref.) with SCE suppression for planar pMOSFETs is also realized. This new SRPD will be the excellent compatible doping method for pMOS FinFETs as well as planar pMOSFETs extension for 32nm node and beyond.

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