scholarly journals Microfabrication of Alkali Vapor MEMS Cells for chip-scale atomic clock

2021 ◽  
Vol 2103 (1) ◽  
pp. 012188
Author(s):  
A Kazakin ◽  
R Kleimanov ◽  
I Komarevtsev ◽  
A Kondrateva ◽  
Y Enns ◽  
...  
Keyword(s):  
Chemical Etching ◽  
Optical Cavity ◽  
Atomic Clock ◽  
Single Step ◽  
Coherent Population Trapping ◽  
Anodic Bonding ◽  
Buffer Gas ◽  
Wet Chemical ◽  
Wet Chemical Etching ◽  
Population Trapping

Abstract The technology of MEMS atomic cells containing rubidium or caesium vapors in an atmosphere of neon buffer gas has been developed. Two-chamber silicon cells containing an optical cavity, shallow filtration channels and a technical container for a solid-state alkali source have been implemented in a single-step process of anisotropic wet chemical etching. To prevent significant undercutting of the filtration channels during etching of the through silicon cavities, the shapes of the compensating elements at the convex corners of the silicon nitride mask have been calculated and the composition of the silicon etchant has been experimentally found. The sealing of the cells has been carried out by silicon-glass anodic bonding at a temperature of 250 °C. For this purpose the LK5 glass which has an increased ionic conductivity in comparison with the conventional glass Borofloat 33 was used. The best microfabricated cells allowed us to obtain estimates of the relative instability of the coherent population trapping resonance frequency at the level of 5 · 10-11 at 1 s.

scholarly journals The Microfabricated Alkali Vapor Cell with High Hermeticity for Chip-Scale Atomic Clock

2022 ◽  
Vol 12 (1) ◽  
pp. 436
Author(s):  
Shuo Jia ◽  
Zhiyuan Jiang ◽  
Binbin Jiao ◽  
Xiaochi Liu ◽  
Yijie Pan ◽  
...  
Keyword(s):  
Laser Intensity ◽  
Atomic Clock ◽  
Coherent Population Trapping ◽  
Wet Etching ◽  
Anodic Bonding ◽  
Buffer Gas ◽  
Single Chip ◽  
Cell Temperature ◽  
Vapor Cell ◽  
Population Trapping

Herein, a microfabricated millimeter-level vapor alkali cell with a high hermeticity is fabricated through a wet etching and single-chip anodic bonding process. The vapor cell, containing Rb and N2, was investigated in a coherent population trapping (CPT) setup for the application of a chip-scale atomic clock (CSAC). The contrast of CPT resonance is up to 1.1% within the only 1 mm length of light interacting with atom. The effects of some critical external parameters on the CPT resonance, such as laser intensity, cell temperature, and buffer gas pressure, are thoroughly studied and optimized. The improved microfabricated vapor cell also exhibited great potential for other chip-scale atomic devices.

Optimization of Buffer Gas Compositions in Atomic Vapor Cell for Coherent Population Trapping Atomic Clock

2019 ◽  
Vol 56 (12) ◽  
pp. 120201
Author(s):  
李云超 Yunchao Li ◽  
胡旭文 Xuwen Hu ◽  
张璐 Lu Zhang ◽  
刘召军 Zhaojun Liu ◽  
张开放 Kaifang Zhang ◽  
...  
Keyword(s):  
Atomic Clock ◽  
Coherent Population Trapping ◽  
Buffer Gas ◽  
Atomic Vapor ◽  
Vapor Cell ◽  
Population Trapping

Decapsulation Techniques for Cu Wire Bonding Package

2009 ◽  
Author(s):  
Dongmei Meng ◽  
Joe Rupley ◽  
Chris McMahon
Keyword(s):  
Laser Ablation ◽  
Thin Layer ◽  
Chemical Etching ◽  
Wire Bonding ◽  
Methods And Techniques ◽  
Wet Chemical ◽  
Wet Chemical Etching ◽  
Reliability Issue ◽  
Etch Time ◽  
Device Technology

Abstract This paper presents decapsulation solutions for devices bonded with Cu wire. By removing mold compound to a thin layer using a laser ablation tool, Cu wire bonded packages are decapsulated using wet chemical etching by controlling the etch time and temperature. Further, the paper investigates the possibilities of decapsulating Cu wire bonded devices using full wet chemical etches without the facilitation of laser ablation removing much of mold compound. Additional discussion on reliability concerns when evaluating Cu wirebond devices is addressed here. The lack of understanding of the reliability of Cu wire bonded packages creates a challenge to the FA engineer as they must develop techniques to help understanding the reliability issue associated with Cu wire bonding devices. More research and analysis are ongoing to develop appropriate analysis methods and techniques to support the Cu wire bonding device technology in the lab.

scholarly journals Controlling the Facet of ZnO during Wet Chemical Etching Its (0001) O‐Terminated Surface

Small ◽  
2020 ◽  
Vol 16 (51) ◽  
pp. 2007045
Author(s):  
Mei Sun ◽  
Bocheng Yu ◽  
Mengyu Hong ◽  
Zhiwei Li ◽  
Fengjiao Lyu ◽  
...  
Keyword(s):  
Chemical Etching ◽  
Wet Chemical ◽  
Wet Chemical Etching

scholarly journals In Situ Study of the Wet Chemical Etching of SiO2 and Nanoparticle@SiO2 Core–Shell Nanospheres

2021 ◽  
Author(s):  
Albert Grau-Carbonell ◽  
Sina Sadighikia ◽  
Tom A. J. Welling ◽  
Relinde J. A. van Dijk-Moes ◽  
Ramakrishna Kotni ◽  
...  
Keyword(s):  
Chemical Etching ◽  
Core Shell ◽  
In Situ Study ◽  
Wet Chemical ◽  
Wet Chemical Etching

Controllable end shape modification of ZnO nano-arrays/rods by a simple wet chemical etching technique

2015 ◽  
Vol 48 (36) ◽  
pp. 365303 ◽  
Author(s):  
Jingchang Sun ◽  
Ting Zhao ◽  
Zhangwei Ma ◽  
Ming Li ◽  
Cheng Chang ◽  
...  
Keyword(s):  
Chemical Etching ◽  
Shape Modification ◽  
Etching Technique ◽  
Wet Chemical ◽  
Wet Chemical Etching

NOHSO4/HF – A Novel Etching System for Crystalline Silicon

2007 ◽  
Vol 62 (11) ◽  
pp. 1411-1421 ◽  
Author(s):  
Sebastian Patzig ◽  
Gerhard Roewer ◽  
Edwin Kroke ◽  
Ingo över
Keyword(s):  
Gas Phase ◽  
Chemical Etching ◽  
Silicon Surface ◽  
Crystalline Silicon ◽  
Etching Solution ◽  
Wide Range ◽  
Ft Ir ◽  
Wet Chemical ◽  
Wet Chemical Etching ◽  
Etching System

Solutions consisting of HF - NOHSO4 - H2SO4 exhibit a strong reactivity towards crystalline silicon which is controlled by the concentrations of the reactive species HF and NO+. Selective isotropic and anisotropic wet chemical etching with these solutions allows to generate a wide range of silicon surface morphology patterns. Traces of Ag+ ions stimulate the reactivity and lead to the formation of planarized (polished) silicon surfaces. Analyses of the silicon surface, the etching solution and the gas phase were performed with scanning electron microscopy (SEM), DR/FT-IR (diffusive reflection Fourier transform infra-red), FT-IR, Raman and NMR spectroscopy, respectively. It was found that the resulting silicon surface is hydrogen-terminated. The gas phase contains predominantly SiF4, NO and N2O. Furthermore, NH4+ is produced in solution. The study has confirmed the crucial role of nitrosyl ions for isotropic wet chemical etching processes. The novel etching system is proposed as an effective new way for selective surface texturing of multi- and monocrystalline silicon. A high etching bath service lifetime, besides a low contamination of the etching solution with reaction products, provides ecological and economical advantages for the semiconductor and solar industry.

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