Abstract
Integrated circuits and certain silicon-based quantum devices require the precise positioning of dopant nanostructures, and hydrogen resist lithography can be used to fabricate such structures at the atomic-scale limit. However, there is no single technique capable of measuring the three-dimensional location and electrical characteristics of these dopant nanostructures, as well as the charge dynamics of carriers and trapped charges in their vicinity. Here, we show that broadband electrostatic force microscopy can be used for non-destructive carrier profiling of atomically thin n-type (phosphorus) and p-type (boron) dopant layers in silicon, and their resulting p–n junctions. The probe has a lateral resolution of 10 nm and a vertical resolution of 0.5 nm, and detects the capacitive signature of subsurface charges in a broad 1 kHz to 10 GHz frequency range. This allows the bias-dependent charge dynamics of free electrons in conducting channels and trapped charges in oxide–silicon interfaces to be investigated. Broadband electrostatic force microscopy can be used to non-destructively image n-type and p-type dopant layers in silicon devices with a lateral resolution of 10 nm and a vertical resolution of 0.5 nm.
Highlights
As the charge dynamics of carriers and trapped charges in their vicinity
scanning tunnelling microscopy (STM) is relatively insensitive to the subsurface[14] when used to measure such structures, scanning microwave microscopy (SMM) can be used nondestructively to determine the 3D location of structures once they are buried within the silicon wafer[15]
In this Article, we show that donor–acceptor interface nanostructures can be fabricated by STM and quantitatively characterized using broadband electrostatic force microscopy
Summary
As the charge dynamics of carriers and trapped charges in their vicinity. Here, we show that broadband electrostatic force microscopy can be used for nondestructive carrier profiling of atomically thin n-type (phosphorus) and p-type (boron) dopant layers in silicon, and their resulting p–n junctions. STM is relatively insensitive to the subsurface[14] when used to measure such structures, scanning microwave microscopy (SMM) can be used nondestructively to determine the 3D location of structures once they are buried within the silicon wafer[15] In this Article, we show that donor–acceptor interface nanostructures can be fabricated by STM and quantitatively characterized using broadband electrostatic force microscopy (bb-EFM). This technique can sense the impedance gradient under different local biasing conditions across a broad frequency range from 1 kHz to 10 GHz, and offers a factor of two improvement in lateral resolution and a factor of five improvement in sensitivity compared with SMM. Bb-EFM measurements made at varying frequencies allow us to estimate the density of oxide-interface trap states, which determine the performance of the final device[16]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
