Observation of dopant profile of transistors using scanning nonlinear dielectric microscopy

Abstract

Abstract. We have demonstrated that scanning nonlinear dielectric microscopy (SNDM) exhibits high performance and high resolution in observing the dopant concentration profile of transistors. In this study, we have measured standard Si samples, which are known to have onedimensional dopant concentration values, calibrated by using conventional secondary ion mass spectrometry (SIMS). Good quantitative agreement between the SNDM signals and dopant density values was obtained by SIMS. We succeeded in visualizing high-resolution dopant profiles in n-and p-type channel MOSFET with 40 nm gate channels. It is considered that SNDM would be an effective method in measuring the quantitative two-dimensional dopant profiles of semiconductor devices. Finally, we have observed the dopant depth profiles of an SRAM memory cell by using SNDM, and succeeded in detecting the insufficient extension ion implantation in the PMOS transistor area.

Calibrated nanoscale dopant profiling using a scanning microwave microscope

“…5,8 In comparison to SMM, scanning nonlinear dielectric microscopy (SNDM) and scanning capacitance microscopy (SCM) provide information on the differential capacitance of semiconductor materials. [9][10][11][12] In SCM, a resonant capacitance sensor is connected to a grounded tip via a transmission line attached to a UHF capacitance sensor. The working frequency of SCM is fixed to $1 GHz, while SMM can operate in a broad band spectrum typically between 1 MHz and 20 GHz.…”

Boxcar Averaging Scanning Nonlinear Dielectric Microscopy

“…As is often done using scanning capacitance microscopy [ 31 ], we can determine the polarity of dominant carriers, p- or n-type, on a local area of a semiconductor from the polarity of the d C /d V signal, and the signal intensity gives local information of carrier concentration with superior sensitivity. If reference samples for calibration can be prepared, the d C /d V imaging can be used for the nanoscale quantitative measurement of non-linear permittivity on dielectrics [ 32 ] and dopant profiling on semiconductors [ 8 , 12 ].…”

“…SNDM was originally devised for imaging electric anisotropy of dielectrics such as ferroelectric domains [ 4 ] and has the potential to become a key technology for ferroelectric probe data storage enabling Tbit/inch 2 recording density [ 5 , 6 ]. The scope of applications has also extended to the nanoscale evaluation of semiconductor materials and devices, including dopant profiling in miniaturized transistors [ 7 , 8 ], imaging the stored charges in flash memories [ 9 ], carrier distribution imaging on SiC power transistors [ 10 ], amorphous and monocrystalline Si solar cells [ 11 , 12 ], and atomically-thin layered semiconductors [ 13 , 14 ]. SNDM and its potentiometric extension can show true atomic resolution in surface dipole imaging on a Si (111)-(7 × 7) surface [ 15 , 16 ] and single-layer graphene on SiC [ 17 ].…”