Random and Ordered Macropore Formation in p-Type Silicon

Vyatkin, A.F.; Старков, В. В.; Tzeitlin, V.; Presting, H.; Konle, J.; König, U.

doi:10.1149/1.1424898

Cited by 74 publications

(60 citation statements)

References 35 publications

(40 reference statements)

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“…When a Si(111) wafer was treated with the Ag catalyst, cylindrical holes inclined to the surface were produced. These morphological properties of the holes are similar to the properties of the holes generated by the electrochemical method, [7,8,15] which makes holes in the <100> direction. Again, there were no noticeable differences in the morphology of the holes between p-type and n-type wafers.…”

Section: Boring Deep Cylindrical Nanoholes In Silicon Using Silver Nasupporting

confidence: 59%

“…These nanoholes are generated in the <100> direction at those positions where small pits were preformed by photolithography. [7,8] Here we report that, without using an electrochemical method, cylindrical nanoholes can be generated by immersing silicon wafers loaded with Ag nanoparticles in a solution containing hydrofluoric acid and hydrogen peroxide. We have been studying the chemical etching of silicon for making an antireflective surface structure (textured structure) in order to increase the efficiency of multi-crystalline Si solar cells.…”

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confidence: 99%

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Boring Deep Cylindrical Nanoholes in Silicon Using Silver Nanoparticles as a Catalyst

Tsujino

Matsumura²

2005

Advanced Materials

229

173

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Silicon shows unique electrochemical properties in solutions containing hydrofluoric acid.[1±4] Cylindrical holes electrochemically formed in silicon in these solutions have recently attracted much attention due to their possible applications in photonic crystals, [5] micromachining, [6] etc. These nanoholes are generated in the <100> direction at those positions where small pits were preformed by photolithography. [7,8] Here we report that, without using an electrochemical method, cylindrical nanoholes can be generated by immersing silicon wafers loaded with Ag nanoparticles in a solution containing hydrofluoric acid and hydrogen peroxide. We have been studying the chemical etching of silicon for making an antireflective surface structure (textured structure) in order to increase the efficiency of multi-crystalline Si solar cells. [9] In the course of this study, we found that the use of Ag nanoparticles as a catalyst is especially effective for making the textured structure. We also found that the catalysis by Ag nanoparticles results in the formation of cylindrical nanoholes in single-crystalline Si wafers when the treatment is continued for a longer time. During the process, the Ag particles gradually sink into the silicon, forming nanoholes as deep as 500 lm and with diameters of about 50 nm. Figure 1 shows a scanning electron microscope (SEM) image of Ag particles deposited on the surface of a p-type Si(100) wafer by electroless plating (see Experimental).[10]The sizes of the particles are mostly between 30 nm and 100 nm. There was no significant difference between the p-type and n-type wafers in densities and size distributions of the deposited Ag particles. In addition, the (100) and (111) orientations did not affect the Ag deposition. Other metal particles were also deposited on Si wafers from solutions containing metal ions, such as Pt, Pd, and Cu.After the deposition of these metal particles, the Si wafers were etched in a mixed solution of 10 % HF and 30 % H 2 O 2 (10:1 v/v) for 30 min in the dark at room temperature. The etched surface of the Si wafers was covered with a microporous Si layer. The microporous Si layer became as thick as 3 lm when Pt particles were used as the catalyst, and showed orange photoluminescence under UV irradiation at 265 nm. Since Pt has a strong catalytic activity in the reduction of hydrogen peroxide, [11] it is assumed that valence-band electrons in Si are drawn through the Si/metal interface as hydrogen peroxide is reduced. As a result, positively charged holes are generated in the Si, leading to the formation of a microporous

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Section: Boring Deep Cylindrical Nanoholes In Silicon Using Silver Nasupporting

confidence: 59%

mentioning

confidence: 99%

Boring Deep Cylindrical Nanoholes in Silicon Using Silver Nanoparticles as a Catalyst

Tsujino

Matsumura²

2005

Advanced Materials

229

173

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“…Since the substrate is p-type, there is no need for back illumination. Following Vyatkin et al (2002) we have made macro PS with HF and Dimethyl Formamide. Figure 2 shows surface profiler view of micro PS and macro PS made on the same p-type wafer.…”

Section: Macro Ps Formation and Optimizationmentioning

confidence: 99%

Composite Si/PS membrane pressure sensors with micro and macro-porous silicon

Sujatha

Bhattacharya

2009

Sadhana

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Porous Silicon (PS) is a versatile material with many unique features making it viable in the field of Microelectromechanical Systems (MEMS). In this paper, we discuss the optimization of formation parameters of micro and macro PS with different porosity and thickness for use in pressure sensors. The optimized material is used in the fabrication of composite Si/PS membranes in piezo-resistive pressure sensors and tested. Pressure sensors with composite membranes have higher sensitivity than those with single crystalline silicon membrane with the sensitivity increasing as the porosity increases. For the same porosity and thickness of the PS layer, Si/micro PS membranes exhibit higher sensitivity than Si/macro PS ones. The offset voltage in these sensors is found to be high and can be due to the stress induced in the membrane during PS formation. Offset voltage and stress values are found to be higher in composite membranes with micro PS as compared to macro PS.

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“…A wide range of pore morphologies can be achieved by adjusting and controlling the parameters of the formation process [6][7][8]. According to the IUPAC, porous structures are typically classified into three main categories: microporous structures with pore size <2 nm, mesoporous structures with pore size between (2 and 50) nm, and macroporous structures with pores >50 nm.…”

Section: Introductionmentioning

confidence: 99%