A model for the etch-stop location on reverse-biased pn junctions

Lapadatu, Daniel; Kittilsland, Gjermund; Nese, Martin; Nilsen, S.M.; Jakobsen, Henrik

doi:10.1016/s0924-4247(97)01687-7

Cited by 15 publications

(15 citation statements)

References 12 publications

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“…Since the backside etch terminates against the depletion region at the pn-junction (Lapadatu et al 1998) the resulting transition between the thin and thick membrane regions is gradual rather than governed by {111} planes as is common when alkali etchants are used. The shape of the resulting transition region is illustrated in Fig.…”

Section: Transition From Thin To Thickmentioning

confidence: 99%

A miniaturized bulk micromachined triaxial accelerometer fabricated using deep reactive etching through a multilevel thickness membrane

2012

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We present the design, fabrication and characterization of an application specific triaxial accelerometer for post-surgery heart monitoring. The accelerometer chip is designed as a 2 9 4 9 1.2 mm 3 chip with nominal acceleration range of ±4 g and frequencies below 50 Hz. It has been fabricated using a multiproject wafer service with an additional deep reactive ion etching process to obtain controlled etch-through of membranes of 3, 23 and 400 lm thicknesses simultaneously. The novelty of the work presented here is the bulk micromachining technique using both deep reactive dry etching and alkali-based anisotropic wet etching of single crystal (100) silicon wafers used to obtain a space efficient design. Proof of concept is demonstrated with preliminary testing, with an acceleration sensitivity of *0.04 mv/V/g for out of plane (z axis) acceleration.

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Section: Transition From Thin To Thickmentioning

confidence: 99%

A miniaturized bulk micromachined triaxial accelerometer fabricated using deep reactive etching through a multilevel thickness membrane

2012

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“…For the experiments with 4EC KOH and for three electrode configuration (3EC) tetramethylammonium hydroxide (TMAH) was used as an electrolyte. For analyzing the data from the 4EC experiments, the model from Lapadatu et al [7] (here after referred to as model A) is applied to calculate the etch stop. This model describes the electrochemical etch stop with a MOS like structure for the electrolyte/semiconductor interface (ESI) together with the pn-junction from the n-doped and p-doped region in the silicon.…”

Section: Introductionmentioning

confidence: 99%

“…In the 3EC experiments, the p-doped region was floating during the electrochemical etching. If the structure does not exhibit a large leakage current and a shallow n + -layer underneath the ESI exists, the model from Lapadatu et al [7] should principally be usable as a first approximation for the electrochemical etch stop. Through the metallic behavior (high conductivity through a high concentration of ions) of the electrolyte, as mentioned by [7], a shallow n + -layer underneath the ESI could be introduced.…”

Section: Introductionmentioning

confidence: 99%

“…If the structure does not exhibit a large leakage current and a shallow n + -layer underneath the ESI exists, the model from Lapadatu et al [7] should principally be usable as a first approximation for the electrochemical etch stop. Through the metallic behavior (high conductivity through a high concentration of ions) of the electrolyte, as mentioned by [7], a shallow n + -layer underneath the ESI could be introduced. In III-D results from model A will be compared with data from experiments, calculations with model B, and results from simulations for 3EC.…”

Section: Introductionmentioning

confidence: 99%

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Modelling of the electrochemical etch stop with high reverse bias across pn-junctions

Szwarc

Frey

Weber

et al. 2015

2015 26th Annual SEMI Advanced Semiconductor Manufacturing Conference (ASMC)

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In this work, the electrochemical etch stop for reverse biases up to 25V at abrupt pn-junctions on 200mm silicon wafers with four and three electrode configuration is investigated. It was found that for such bias conditions across the pn-junction the etch results differ significantly from the prediction of an established model for the electrochemical etch stop under open circuit potential conditions with four electrode configuration. The established model for a semiconductor with pn-junction where the p-doped region is in contact with the electrolyte describes the interface of the p-doped region and the electrolyte with an induced shallow n+ electrical layer. Thus - for this model - the space charge region in the p-doped region introduced by the electrolyte/semiconductor interface only depends on temperature and doping concentration. A new model is introduced which enables the modeling of the electrochemical etch stop with other electrolytes (with different redox potentials), voltage conditions, and for three or four electrode configurations. The new model describes the structure of the electrolyte/semiconductor interface as a Schottky contact together with the pn-junction in the semiconductor. Experimental data from three and four electrode configuration are critically compared with predictions from the new and the established analytical models as well as with numerical simulations. The new model analytically calculates the electrochemical etch stop well for three and four electrode configuration if conditions like Fermi level pinning are included. The established model underestimates the electrochemical etch stop with four electrode configuration, but shows a good agreement with the results from three electrode configuration experiments

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“…A simple etch cell with a three electrode configuration is schematically presented in figure 3.24 [Bey96]. Examples are presented in [Lap98,Kühl94,Ace94]. The necessity of an electric field and with it the necessity of an etch cell is disadvantageous.…”

Section: Influence Of Dopingmentioning

confidence: 99%

Orientation Dependent Etching of Silicon

Shape and Functional Elements of the Bulk Silicon Microtechnique

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The etching as a process of micromachining silicon wafers strives for an even removing of material from the surface which will be displaced parallel to itself as a consequence. The distance d between the original and the etched surface describes the thinning of the wafer or the depth of an etched deepening. A characteristic parameter of the etching process is the etch rate v as the ratio of the etch distance d to the etching time t:

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A model for the etch-stop location on reverse-biased pn junctions

Cited by 15 publications

References 12 publications

A miniaturized bulk micromachined triaxial accelerometer fabricated using deep reactive etching through a multilevel thickness membrane

A miniaturized bulk micromachined triaxial accelerometer fabricated using deep reactive etching through a multilevel thickness membrane

Modelling of the electrochemical etch stop with high reverse bias across pn-junctions

Orientation Dependent Etching of Silicon

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