Optimization of the dynamic range of SIMS depth profiles by sample preparation

Criegern, R. v.; Weitzel, L.; Zeininger, H.; Lange-Gieseler, R.

doi:10.1002/sia.740150704

Cited by 11 publications

(2 citation statements)

References 8 publications

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“…The effectiveness of in situ mesas studied by Gillen, 2 minichip and dot etching methods developed by von Criegern et al, 3,4 and ex situ mesas using focused ion beam ͑FIB͒ by Mckinley et al,5 is well established where such methods typically produce gains in detection limits of boron implant profiles by approximately ten times compared to conventional depth profiles. An often tried and effective approach is the use of a mesa structure ͑or a structure of similar effect͒, formed either by ion milling, chemical etching, or physical arrangement, to essentially eliminate the crater sidewall, and thus its contribution.…”

Section: Introductionmentioning

confidence: 99%

“…An often tried and effective approach is the use of a mesa structure ͑or a structure of similar effect͒, formed either by ion milling, chemical etching, or physical arrangement, to essentially eliminate the crater sidewall, and thus its contribution. [2][3][4][5] This study describes a relatively quick and effective method of constructing a mesa structure, using an automated dicing saw, in order to minimize crater sidewall contribution in depth profiles of high dose samples. Its usefulness is sufficient to motivate at least one manufacturer to engineer mesa scanning circuitry into their commercial SIMS profiler.…”

Section: Introductionmentioning

confidence: 99%

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Mesa sample preparation for secondary ion mass spectrometry depth profiling using an automated dicing saw

Guenther¹,

Jiang²,

Kim³

et al. 2009

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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The use of secondary ion mass spectrometry to verify dopant profiles, either for process control or for simulation modeling, is an established practice in semiconductor fabrication, where precise dopant concentrations are integral to device performance. Of the many understood secondary ion mass spectrometry (SIMS) artifacts, the crater edge effect is one that can limit critical detection limits under conventional SIMS profiling of high dose samples. The use of a mesa structure to eliminate crater sidewall contribution is a proven remedial method, although with practical limitations associated with each iteration of the approach. This work explored a method of constructing a mesa structure using an automated dicing saw. The mesa structures were prepared relatively quickly, taking only about 20min to construct a six mesa array per sample. Scanning electron microscopy images of cross sectioned mesa structures indicating excellent slope was achieved, without erosion of the mesa surface. Depth profiles from two examples of high dose samples were collected by both standard SIMS and mesa SIMS. Analogous mesa profiles demonstrated between 20 and 5 times gains in detection limits compared to the standard SIMS profiles, comparable to gains achieved in other mesa work. Mesa profiles appeared to be accurate, void of mesa induced artifacts, and repeatable, based on examinations of matrix intensities and peak shapes compared to the standard profiles.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mesa sample preparation for secondary ion mass spectrometry depth profiling using an automated dicing saw

Guenther¹,

Jiang²,

Kim³

et al. 2009

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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High dynamic range SIMS depth profiling on in situ ion‐beam‐generated mesas using the ion microscope

Gillen

1992

Surface & Interface Analysis

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The dynamic range of SIMS depth profiles of highdose ion implants can often be improved by removing the influence of the highly doped crater walls from the depth profile. This is accomplished either by collapsing the primary beam raster or by using specialized sample preparation techniques such as the mini-chip or dot-etching methods developed by von Criegern et al. The main limitations with the sample preparation techniques are that they are labor and time-intensive and are not applicable to aii substrate types. By a simple modification of the raster circuits of an ion microscope, it is possible to generate, by sputtering, a mesa structure that is subsequently profiled under normal conditions. This approach offers a rapid, flexible method of mesa preparation that is amenable to all sample materials. The principal disadvantage with the use of the ion microscope for this analysis is that a significant memory effect can result from the dopant species that are sputtered during the preparation of the mesa structure.

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Quantitative study of background signals from crater edges and surroundings in depth profiling of small areas with secondary ion mass spectrometry

Meuris

Bisschop

Vandervorst

1993

Surface & Interface Analysis

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A theoretical model is presented to calculate the redeposition of ions and neutrals generated during sputter bombardment in a secondary ion mass spectrometry (SIMS) measurement. This model is compared with measurements of boron in silicon in an on-chip geometry, i.e. the analysis of low doping levels of an impurity in an area surrounded by a region that contains high amounts of this impurity. The present results indicate that the ion acceptance profile of the secondary ion beam and the redeposition of ions and neutrals generated during the sputtering form the limiting factors in small-area on-chip analysis. The non-ideal definition of the acceptance profile is solved by superimposing an electronic gate onto the optical gate of the instrument. For the analysis of B in Si and Si in GaAs and AI,Ga, -xAs, the use of Cs' reduces the background signal of the measurement compared with 0,'. ~~ ~~~ INTRODUCTIONSecondary ion mass spectrometry (SIMS) analysis of dopants, with its unparalleled sensitivity and depth resolution, has contributed in many ways to the progress of semiconductor technology by providing adequate feedback on the different processing steps. In many cases this analysis can be made on uniform test wafers, which provides ample material for the analysis. However, in a number of cases such a test wafer does not exist or one is interested in the effects of full processing on the dopant profiles in small areas. It then becomes necessary to perform a SIMS analysis on-chip in a well-determined (usually small) area.In the present paper we have investigated the implications and problems of such an on-chip analysis, bearing in mind that this sometimes implies measuring the wanted dopant profile in a small area surrounded by material containing very high amounts of the element of interest. To explore this in more detail, a special test sample has been made to simulate this situation and to make a quantitative evaluation of the mechanisms of interest possible. The test sample consists of squares, of various sizes, etched into a boron phosphor silicate Glass (BPSG) layer. ~~~~ EXPERIMENTALPreliminary experiments were performed on a uniformly implanted wafer whereby the field of view was continuously reduced. As expected, the reduction in sensitivity as the area is decreased was found to scale * Author to whom correspondence should be addressed. proportionally with the area being analysed when using the field aperture to reduce the analysed area. In fact it was found that the loss in sensitivity was less than expected based on area ratios, when changing to the small areas with using the transfer lens settings, because this increases the collection efficiency. This implies that a reduction of the analysed area with a 150 pm diameter down to 12 pm diameter generates no extra problems. The test sample (see Fig. 1) prepared consists of squares of Si, of size 1 pm-1 mm, etched in an SiO, layer (800 nm doped layer with 5% B and 5% P on a 200 nm undoped layer).'.' The squares themselves received a "B implantation at 40 keV o...

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Optimization of the dynamic range of SIMS depth profiles by sample preparation

Cited by 11 publications

References 8 publications

Mesa sample preparation for secondary ion mass spectrometry depth profiling using an automated dicing saw

Mesa sample preparation for secondary ion mass spectrometry depth profiling using an automated dicing saw

High dynamic range SIMS depth profiling on in situ ion‐beam‐generated mesas using the ion microscope

Quantitative study of background signals from crater edges and surroundings in depth profiling of small areas with secondary ion mass spectrometry

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