Boron etch-stop in TMAH solutions

Steinsland, E.; Nese, Martin; Hanneborg, A.; Bernstein, Ralph; Sandmo, Halle; Kittilsland, Gjermund

doi:10.1016/s0924-4247(97)80047-7

Cited by 48 publications

(32 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, there is a wide variation in reported value of activation energy for TMAH etching; both higher and lower values of activation energies compared to our value (0.49 eV) have been reported previously (Biswas and Kal 2006;Choi et al 1999;Shikida et al 2000;Steinsland et al 1996). The activation energy (0.34 eV) for EDP etching is quite well matched with the value (0.33 eV) quoted by Seidel et al (1990a, b).…”

Section: Activation Energysupporting

confidence: 89%

“…Moreover, majority of the studies on wet anisotropic etching are related to Si (100) (Bhandari et al 2010;Bhat et al 2003;Biswas and Kal 2006;Choi et al 1999;Lee et al 2009;Ni et al 2005;Sato et al 1999;Seidel et al 1990a, b;Shikida et al 2000;Tanaka et al 2004;Yang et al 2005) wafers compared to Si (110) (Dutta et al 2009;Steinsland et al 1996;Uenishi et al 1995). But deep vertical features can't be fabricated using Si (100) wafers due to the presence of slanted (111) planes (Seidel et al 1990a, b;Lee et al 2009;Steinsland et al 1996). In comparison, Si (110) wafers has a set of (111) planes that are normal to the surface of the wafers as shown schematically in Fig.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Comparison of etch characteristics of KOH, TMAH and EDP for bulk micromachining of silicon (110)

et al. 2011

View full text Add to dashboard Cite

Bulk micromachining in Si (110) wafer is an essential process for fabricating vertical microstructures by wet chemical etching. We compared the anisotropic etching properties of potassium hydroxide (KOH), tetra-methyl ammonium hydroxide (TMAH) and ethylene di-amine pyro-catechol (EDP) solutions. A series of etching experiments have been carried out using different etchant concentration and temperatures. Etching at elevated temperatures was found to improve the surface quality as well as shorten the etching time in all the etchants. At 120°C, we get a smooth surface (Ra = 21.2 nm) with an etching rate 12.2 lm/min in 40wt% KOH solution. At 125°C, EDP solution (88wt%) was found to produce smoothest surface (Ra = 9.4 nm) with an etch rate of 1.8 lm/min. In TMAH solution (25wt%), the best surface roughness was found to be 35.6 nm (Ra) at 90°C with an etch rate of 1.18 lm/min. The activation energy and preexponential factor in Arrhenius relation are also estimated from the corresponding etch rate data.

show abstract

Section: Activation Energysupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Comparison of etch characteristics of KOH, TMAH and EDP for bulk micromachining of silicon (110)

et al. 2011

View full text Add to dashboard Cite

show abstract

“…Widely used methods to control the microdiaphragm to the desired thickness are the etched-time stop, the boron etchstop [14], the silicon-on-insulator (SOI) substrate [15] and the electrochemical etch-stop methods [16]. One disadvantage of the etched-time stop method is that the variation of etch rate, which can occur with certain etchants, and the variation of silicon thickness can lead to thickness error, which may be a large percentage of the desired diaphragm or beam thickness.…”

Section: Introductionmentioning

confidence: 99%

Anisotropic etching and electrochemical etch-stop properties of silicon in TMAH:IPA:pyrazine solutions

Chung

2001

Met. Mater. Int.

View full text Add to dashboard Cite

Anisotropic etching and electrochemical etch-stop properties of single-crystal silicon in tetramethylammonium hydroxide (TMAH): isopropyl alcohol (IPA) solutions containing pyrazine were investigated. With the addition of IPA to TMAH solution, an improvement in flatness on the etching front and a reduction in undercutting were observed, but the etch rate on (100) silicon decreased. However, the (100) silicon etch rate is improved by the addition of pyrazine. An etch rate of 0.8 μm/min on (100) silicon, which is faster by 13% than a 20 wt.% solution of pure TMAH, is obtained using 20 wt.% TMAH:0.005 g/ml pyrazine solutions, but the etch rate on (100) silicon is decreased if there is an increase in the amount of pyrazine in the solution. With the addition of pyrazine to a 25 wt.% TMAH solution, no significant variations in flatness on the etching front were observed and the undercutting ratio was reduced by 30~50%. The addition of pyrazine to TMAH:IPA solutions increased the etch rate of (100) silicon, thus the time required by the etch-stop process was shortened. The current-voltage (I-V) characteristics of n-and p-type silicon in TMAH:IPA:pyrazine solutions were obtained. The passivation potential (PP) of n-and p-type silicon was obtained and the applied potential was selected between n-and p-type silicon PPs. The electrochemical etch-stop method was applied to the fabrication of 801 silicon microdiaphragms of 20 μm thickness on a 5-inch silicon wafer. The average thickness of fabricated 801 microdiaphragms on one wafer was 20.03 μm and the standard deviation was ±0.26 μm. The silicon surface of the etch-stopped microdiaphragms was extremely flat with no noticeable taper or non-uniformity. The benefits of the electrochemical etch-stop method for the anisotropic etching of silicon in TMAH:IPA:pyrazine solutions become apparent when reproducibility of silicon microdiaphragm thickness for mass production is realized. The results indicate that use of the electrochemical etch-stop method for the anisotropic etching of silicon in TMAH:IPA:pyrazine solutions provides a powerful and versatile alternative process for fabricating highyield silicon microdiaphragms.

show abstract

“…[35] The doping concentration of the Si to be etched to form the recess also strongly impacts on the etching: During etching, Boron-doped Si forms borosilicate glass on the exposed Si surface, which acts to create etch stop if the boron doping concentration exceeds 10 18 cm -3 . [39] A clean Si surface is mandatory for high-quality epitaxial films. In-situ baking at >800ºC in a H 2 ambient is the conventional method to remove residual oxygen from the Si surface before the epi deposition.…”

mentioning

confidence: 99%

Review paper: Advanced source and drain technologies for low power CMOS at 22/20 nm node and below

Song

Blatchford

2011

Electron. Mater. Lett.

View full text Add to dashboard Cite

TX 75243, U.S.A As device dimensions scale, optimization of the source and drain portions of MOSFETs becomes more important in order to reduce parasitic resistance and capacitance, and thus ultimately improve overall device performance. Reduction of parasitic resistance requires careful optimization of dopant incorporation and activation. In current cutting-edge technologies, the source/drain region also plays a key role in improving channel carrier mobility though process-induced strain. Introducing various alloys into NiSi and/or implanting appropriate elements has shown to give significant reduction of the Schottky barrier height between NiSi and Si, thereby improving resistance. In this paper, we review key aforementioned source and drain engineering technologies relevant to the 22/20 nm logic technology node and below.

show abstract

Boron etch-stop in TMAH solutions

Cited by 48 publications

References 5 publications

Comparison of etch characteristics of KOH, TMAH and EDP for bulk micromachining of silicon (110)

Comparison of etch characteristics of KOH, TMAH and EDP for bulk micromachining of silicon (110)

Anisotropic etching and electrochemical etch-stop properties of silicon in TMAH:IPA:pyrazine solutions

Review paper: Advanced source and drain technologies for low power CMOS at 22/20 nm node and below

Contact Info

Product

Resources

About