Mapping two-dimensional arsenic distributions in silicon using dopant-selective chemical etching technique

Abstract

Articles you may be interested inTwo-dimensional dopant concentration profiles from ultrashallow junction metal-oxide-semiconductor field-effect transistors using the etch/transmission electron microscopy method Transmission electron microscopy ͑TEM͒ image contrast was used to characterize doping-dependent etching of n ϩ /p junctions in silicon. The local variations in crystal thickness give rise to the appearance of thickness fringes which may be interpreted as two-dimensional iso-concentration contours that map the dopant distribution. The etchant solution used for selective chemical etching of TEM samples prepared using wedge technique was modified to reduce the etch rate and maintain high selectivity to the n ϩ doped region. The two-dimensional dopant profiles were quantified by calibrating against one-dimensional secondary ion mass spectroscopy data and also compared with one-dimensional spreading resistance analysis data.

Transmission Electron Microscopy Study of Two-Dimensional Dopant Profiling in Metal-Oxide-Semiconductor Field Effect Transistor Test Structures and Devices

“…This behavior was attributed to the carrier spilling effect and the bevel geometry. 7,13,14 Within the regions with carrier concentrations higher than ϳ1 ϫ 10 18 cm Ϫ3 , the SRP data are in reasonable agreement with the SIMS results, considering that the estimate of error in SRP measurements was Ϯ20%. The experimental SIMS data (As concentration) of the samples are in very good agreement with the simulated SIMS results of the experimental conditions.…”

“…1 The shrinkage in the device dimensions requires assessment techniques with high spatial resolution which are capable of obtaining carrier distribution and junction depth, in particular, the lateral diffusion of dopants below the gate area of metal-oxide-semiconductor (MOS) devices. Techniques such as transmission electron microscopy (TEM), [2][3][4][5][6][7] scanning electron microscopy (SEM), 8 and atomic force microscopy (AFM) 9 have been successfully employed to obtain experimental two-dimensional (2D) dopant profiles in semiconductor devices. A basic idea of these techniques is related to a combination of the selective chemical etching of doped layers and the microscope examination of the etched surface.…”

Two-dimensional dopant profiling in semiconductor devices by electron holography and chemical etching delineation techniques with the same specimen

“…Conventionally, the chemical etching delineation method has been used for 2D dopant profile observation involving selective chemical etching according to the concentration level of dopant by dipping the thin TEM specimens in the chemical etchant after their preparation [8][9][10][11][12][13][14]. After the etching, junction delineated profiles are observed by means of electron microscopy.…”

“…The resulting interference pattern (hologram) can be used to recover both the phase shift and the amplitude of the transmitted wave. Recently, this technique has been employed for 2D dopant profiling of semiconductor devices [3][4][5][6][7].Conventionally, the chemical etching delineation method has been used for 2D dopant profile observation involving selective chemical etching according to the concentration level of dopant by dipping the thin TEM specimens in the chemical etchant after their preparation [8][9][10][11][12][13][14]. After the etching, junction delineated profiles are observed by means of electron microscopy.…”

Advance static random access memory soft fail analysis using nanoprobing and junction delineation transmission electron microscopy

“…6,7 Another solution for 2D dopant characterization, that has been used for decades, is the method of junction etch or dopant-selective etching. [8][9][10][11][12][13][14] This method is done by first staining the sample cross section with an appropriate chemical solution to transfer the dopant profile into a topography profile then imaging it in an electron microscope. Nevertheless, the etch process is rather complex and the result depends on a variety of parameters, such as specimen thickness, etching recipe, etching time, and etching temperature, which usually leads to poor sample reproducibility.…”