Challenges of 2-D (3-D) device doping process and doping profiling metrology

Abstract

The appearance of 3-D devices and structures has changed the doping technologies and doping profiling metrology. This change also implies that novel concepts for 3-D dopant and carrier profiling measurements are necessary. 1.5-D SIMS can be used to study dopant incorporation in 3-D structures. SSRM and electron holography methods have been developed and well-established on 2-D cross-sectional doping profiling measurements. Although SSRM and electron holography approaches are inherently 2-D, extensions towards 3-D structures are capable either by the dedicated design of test structures or by the approaches of mechanical slicing and polishing. Thanks to the new 2-D (3-D) doping profiling measurements, PLAD process has been demonstrated beneficial on 3-D device manufacturing.

Conformal doping strategy for fin structures: tailoring of dopant profile through multiple monolayer doping and capping layer control

“…Characterization of the non-planar structure with x-ray techniques such as x-ray photoelectron spectroscopy (XPS) and x-ray diffraction cannot be obtained. Besides, accurate dopant profiling in the fin structure using time-of-flight secondary ion mass spectrometer (ToF-SIMS) is very challenging [7,9]. Therefore, we prepared a planar sample with the surfaces that appear in the (100)-oriented fin structure, including the pristine (100), damaged (110) and damage cured (110) surface.…”

“…Non-planar nanoelectronic devices, such as fin field-effect transistors (FinFETs) and gate-all-around FETs, have been developed and applied as a solution to the limitations of planar CMOS technology [1][2][3][4]. However, the transition to these advanced non-planar devices with vertical geometry has posed technological difficulties in fabricating nanostructures with precisely controlled atomic composition [5][6][7]. Especially, ion-implantation, the standard doping technique for controlling the electrical properties of semiconductor materials, suffers from serious compatibility problems for nanoscale and vertical devices [7][8][9][10].…”

“…However, the transition to these advanced non-planar devices with vertical geometry has posed technological difficulties in fabricating nanostructures with precisely controlled atomic composition [5][6][7]. Especially, ion-implantation, the standard doping technique for controlling the electrical properties of semiconductor materials, suffers from serious compatibility problems for nanoscale and vertical devices [7][8][9][10]. It utilizes energetic species with high straightness, which causes crystal damage and has limitations in the exact positioning of dopant atoms.…”