Photoelectrochemical Etching Process Research Articles

Laser Produced Hydrophilic and Hydrophobic Silicon Surfaces

Two lasers were utilized for silicon processing using photoelectrochemical etching and laser texturing in order to produce nano/micro structures, respectively. Photoelectrochemical etching process utilizes a CW diode laser of 532 nm wavelength was used to support electrochemical etching for both n-type and p-type conductivity. While laser texturing process was employed using pulsed fiber laser of 1064 nm wavelength. Various characterization methods were devoted to examine silicon micro/nanostructures surfaces produced by lasers. These methods include AFM, SEM and Raman scattering to provide clear evidence about formation of micro/nanostructures abundant at silicon surfaces. Moreover, FTIR analysis for the laser produced silicon surfaces could emphasize whether the resultant silicon surface is hydrophilic or hydrophobic. Image analysis software adopted a side view micro image was used to measure the contact angle between the water droplet and silicon micro/nano-surfaces. It is found that the laser produced silicon nanostructure by photoelectrochemical etching creates a hydrophobic surface and even super hydrophobic with contact angle of 130 degrees for 50 nm average size. In addition, utilizing fiber laser of high repetition rate for laser texturing produces microstructures that are super hydrophilic with contact angle could reach 8 degrees for a surface dimension of 50 μm.

Surface roughness-controlled foam-like GaN fabricated by the change H2O concentration in ionic liquid etchant solution via photoelectrochemical etching

The structure and morphology of foam-like GaN (F-GaN) was significant to the performances of nanodevices, especially optoelectronic devices. Here we present a reasonable way to regulate the surface roughness on F-GaN, by the change of H2O concentration in the etching system. Ionic liquid (ILs) 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([EMIM][OTF]) was used as the etchant for the photoelectrochemical etching (PECE) process. With the H2O concentration changed from 0 to 5 % in the etchant solution, the surface roughness of F-GaN was reduced from 57.6 to 34.6 nm. In addition, to describe the role of H2O in the etching procedure, a physical impact etching mechanism was proposed. These results further promoted the potential value of F-GaN in the optical field.

Impact of porosity on the structural and optoelectronic properties of nanoporous GaN double layer fabricated via combined electrochemical and photoelectrochemical etching

Nanoporous GaN double layer structures with porosity ranging from 10% to 60% are fabricated via a combined electrochemical etching and photoelectrochemical etching process. The porosity as well as the variation in the size and shape of the nanopores are controlled by regulating the applied voltage in the etching process. With the increase in the porosity, the biaxial stress and reflectance index of the nanoporous GaN double layer decrease from 0.74 GPa and 2.4 to 0.42 GPa and 2.0, respectively. Furthermore, the photoluminescence intensity of the InGaN/GaN multi-quantum wells grown on the nanoporous GaN is approximately three times higher than that on the as-grown reference GaN. The enhanced photoluminescence intensity can be attributed to the porosity controlled through the incorporated nanopores, which increase the light extraction efficiency. The light generated in the active layer is further extracted due to scattering by the nanopores.

Preparation high quality ethanol gas sensor by modifying porous silicon (PS) surface with carbon nanotube (CNTs)

In the study, the high-quality gas sensor for ethanol was prepared by modified porous silicon (PS) with a thin layer of carbon nanotube. The PSi samples have been prepared by using the photoelectrochemical etching (PECE) process at various current densities J = 12, 24, and 30 mA/cm2 with 10 min etching time and Hydrofluoric acid concentration (HFC) of 40%. All samples (PSi and MWCNTs/PSi) were analyzed using X-ray diffraction (XRD), field emission Scanning electron microscopy (FE-SEM), Fourier Transform Infrared Spectroscopy (FTIR), and Atomic Force Microscopic (AFM), to determine the structural, morphological, and surface bond configuration. As a result, the Photoluminescence (PL) test was performed on all samples using the PL system in order to calculate the energy band gap for all samples. Then the PSi and MWCNTs/PSi samples were applied as ethanol gas sensor at room temperature (RT). The results showed that the best sensitivity of ethanol gas was about (2.1912349) at a concentration of 500 parts per million (ppm) for MWCNTs/PSi sample compared to PSi surface, it was about (1.709) under the same used conditions at etching current density 30 mA/cm2. The MWCNTs/PSi layers serve as low-cost and high-quality ethanol gas sensors. The carbon nanotube used to replace expensive materials used in gas sensors that function at low temperatures, including room temperature. The materials have an exceptionally high surface-to-volume ratio (increasing surface area), ease of fabrication, and compatibility with silicon microelectronics manufacturing processes.

Fabrication of (ZnO)x: (Cu)1-x/PSi Solar Cell Using Laser Induced Plasma Technique

Fabrication of PSi is generated successfully depending upon photo-electrochemical etching process. The purpose is to differentiate the characterization of the PSi monolayer based on c-silicon solar cell compared to the bulk silicon alone. The surface of ordinary p-n solar cell has been reconstructed on the n-type region of (100) orientation with resistivity (3.2.cm) in hydrofluoric (HF) acid at a concentration of 2 ml was used to in order to enhance the conversion efficiency with 10-minute etching time and current density of 50 mA/cm2, The morphological properties (AFM) as well as the electrical properties have been investigated (J-V). The atomic force microscopy investigation reveals a rugged silicon surface with porous structure nucleating during the etching process (etching time), resulting in an expansion in depth and an average diameter of (40.1 nm). As a result, the surface roughness increases. The electrical properties of prepared PS, namely current density-voltage characteristics in the dark, reveal that porous silicon has a sponge-like structure and that the pore diameter increases with increasing etching current density and the number of shots increasing this led that the solar cell efficiency was in the range of (1-2%), resulting in improved solar cell performance.

Synthesis of ZnO nanostructures by hydrothermal method deposited on porous silicon for photo-conversion application

The hydro-thermal ZnO nanostructure synthesis is described in this paper. ZnO nanoparticles have been studied with the use of a scanning electron microscope (SEM), and X-ray diffraction (XRD) confirmed the formation of ZnO's hexagonal structure of the wurtzite. The produced nanostructure's average crystallite size was 21 nm. From UV–Vis absorption spectra, the bandgap of ZnO nanostructures was estimated, and the bandgap was 3.0 eV for ZnO. The porous silicon (PS) layers have been made from n-type silicon (100) orientation using the photo-electrochemical etching (PECE) process. Electrical attributes and a photodetector are utilized to characterize the product. The findings indicate that such hydrothermal synthetic method may produce high-quality ZnO nanoparticles. The photo-conversion characteristics of ZnO NPs/PS are improved, resulting in an increase in the responsivity. As a result, ZnO NPs/PS might be employed as a photodetector with a broad wavelength spectral range.

Influence of magnetic field on the characteristics of n-type PSi prepared by photo-electro-chemical etching process

The surface uniformity of porous silicon (PSi) morphologies will enhance the overall properties of the PSi layer. In this study, the role of perpendicular magnetic field (MF) on structural, optical, and electrical properties of (PSi) substrates are reported. The (PSi) is prepared with a photo-electrochemical etching process in the front-side illumination pathway with and without a perpendicular magnetic field (MF). The application of (MF) on the path of the electric charge carrier leads to modify the morphologies of PSi surface. The pores shape, sizes, orientation, and homogeneity, and electrical properties will vary with the (MF). The role of (MF) will contribute to an increase in the number of pores and decrease the overlapping process. And also, promotes the orientation of the relatively more defined pores across the Psi surface. The observed noticeable changes in PL spectra, electrical properties, and charge carrier transport mechanisms may be owing to the surface reconstruction process. The influence of (MF) on the characteristics of Au thin layer / PSi/c-Si/Al structures will lead to converting its behavior from the resistor to Schottky-like junction.

White, blue and green emission from Si QDs derived from zinc incorporated porous silicon

This paper reports the tailored visible light emission (blue, green and white) traits of the colloidal silicon quantum dots (SiQDs) integrated with zinc (ZnSiQDs). These QDs were derived from the PSi etched with Zn powder. The ZnSiQDs was prepared via the photo-electrochemical etching process (40 mA/cm2 for 20 min) of the n-type Si wafer immersed inside the solution made from the hydrofluoric (HF) acid to ethanol (ET) volume ratios of 7:1 and 7:3 with the Zn powder (0.17 g) inclusion. The as-prepared samples (named as ZnSiQDs-7:1 and ZnSiQDs-7:3) were characterized to determine the influence of HF:ET on their structure, morphology and optical characteristics. The XPS analyses of the samples revealed the formation of ZnO. The FESEM images exhibited the growth of PSi layer of thickness 8.192 μm and 7.073 μm for the ZnSiQDs-7:3 and ZnSiQDs-7:1 samples, respectively. The EFTEM image analyses showed the nucleation of the ZnSiQDs of average diameter 2.7 nm (for ZnSiQDs-7:3) and 1.33 nm (for ZnSiQDs-7:1). The band gap energy for both samples estimated from the absorption spectra was 3.6 eV. The emission spectra of the studied ZnSiQDs under three different excitation wavelengths disclosed the intense visible peaks (blue, green and white) in the range of 385–700 nm. This observation was mainly ascribed to the effects of quantum confinement and ZnO surface layer on the SiQDs that minimized the silicon oxidation. It is established that by controlling the HF to ET volume ratio the visible luminescence of the ZnSiQDs can be customized, useful for diverse optoelectronic applications.

Fabrication of Recessed-Gate AlGaN/GaN Hemts Utilizing Contactless Photo-Electrochemical (CL-PEC) Etching

AlGaN/GaN HEMTs are promising devices to attain both high-power and high-speed switching operation for the use in next-generation power electronics circuits. From the viewpoint of fail-safe and low-power consumption design, however it is necessary to attain normally-off operation with a positive threshold voltage (V th). One of the promising approaches to attain such operation is adopting a recessed-gate structure, which can be fabricated by thinning the AlGaN layer beneath the gate electrode. We have reported the photo-electrochemical (PEC) etching process for the fabrication of the recessed-gate AlGaN/GaN HEMTs was promising to improvement of transfer characteristics of the device and control of V th[1]. In this study, we developed the contactless PEC (CL-PEC) etching process[2-5], whose experimental system was simpler than that of conventional PEC etching process, for the fabrication of the recessed-gate structure. Consequently, for the devices fabricated by CL-PEC, the etched surface was very smooth such as the as-grown surface. The device characteristics improved to be compared with those without the recessed-gate fabrication process.We used an i-Al0.24Ga0.76N (28.4 nm)/i-GaN heterostructure grown by metal organic vapor phase epitaxy on a semi-insulating SiC substrate as a sample. A Ti ohmic contact was formed on the edge of the sample as a cathode pad which was not connected to the outer circuit. The CL-PEC etching process was conducted by only dipped the sample into 0.025 M K2S2O8 aqueous solution (pH = 3.4) under illumination of UVC light, whose center wavelength was 260 nm and the intensity was 4 mW/cm2. The distance between UVC light source and the surface of sample was set to 4 cm, where the optical path in the solution was fixed at 0.5 cm. As an etching mask, the lamination film of SiN (100 nm) and photoresist was formed by sputtering and photolithography process. After the etching, TMAH treatment was conducted in recessed-gate region. An inductive-coupled-plasma reactive-ion-etching (ICP-RIE) was conducted for the device isolation. The source-drain electrodes (Ti/Al/Ti/Au), Schottky-gate and MIS-gate electrodes were fabricated by a standard evaporation process. The various devices with different gate lengths (3, 5 and 10 µm) were fabricated on the same chip. The gate width for all device was designed to be 100 μm.The etching depth and the surface morphology were evaluated by AFM technique after the CL-PEC etching. An etching rate of AlGaN layer was very slow (< 1.0 nm/min) under the optimal condition, leading to the precise control of the residual thickness of the AlGaN layer. In addition, the self-termination of the etching was observed. The etching was stopped in the AlGaN layer, leaving a thickness of 6 nm. The surface after the etching was very smooth, where the root-mean-square (RMS) value of roughness was 0.4 nm (in 7 × 7 μm2 area). The drain current-voltage (I DS-V DS) characteristics of Schottky recessed-gate HEMTs showed good pinch-off behavior. The drain leakage currents with a reverse bias decreased and the V th was shifted in the positive direction from -3.4V (planar-gate devices) to 0 V. The value of sub-threshold slope (SS), obtained from the transfer characteristics, was smaller than that obtained for the planar-gate HEMTs. In addition, the standard deviation, σ, of the V th was 5.7 mV which was much smaller than that of the planar-gate devices. These results show that the uniformity of device performance enhanced after the CL-PEC process. The MIS recessed-gate HEMTs also showed good I DS-V DS characteristics with constant saturation currents and pinch-off behavior. As similar to the Schottky HEMTs, shift of V th in the positive direction, and the improved V th uniformity were observed. In addition to this, the MIS gate structure has the advantage that the device operates under positive bias by reducing gate leakage currents. This feature is promising for increasing the drain current reduced by the recess gate structure. In conclusion, excellent electrical properties such as low-leakage currents and precise control of V th for recessed-gate AlGaN/GaN HEMTs were achieved by the low-damage CL-PEC etching with the self-terminated nature.Acknowledgements: This work was supported by JSPS KAKENHI-JP16H06421, 20H02175.[1] Y.Kumazaki et al., JJAP, 121, 184501 (2017). [2] F.Horikiri et al., APEX, 12, 031003 (2019) [3] M.Toguchi et al., APEX, 12, 066504 (2019). [4] F.Horikiri et al., IEEE Trans. Semicond. Manuf., 32, 489 (2019). [5] K.Miwa et al., APEX, 13, 026508 (2020). Figure 1

Laser micro/nano machining of silicon

This work investigate the formation of micro/nanostrucutred layers of silicon wafers having various conductivity types emphasizing the crucial role of laser in stimulating the etching reaction as well as controlling the silicon surface structures in photochemical and photoelectrochemical etching processes. A CW visible laser beam was used to synthesize silicon nanostructures of various morphologies in this work. It is found in photochemical etching that short laser wavelengths produce a thin porous layer compared to longer laser wavelengths which are appropriate for thicker porous layers. SEM investigation reveals the formation of different nanostructures that were synthesized by photochemical etching. Results show that optimum porosity of 70 %, 80 %, and 90 % are achievable for n, p, and p-n silicon respectively when using a current density of 25 mA/cm2in the photoelectrochemical etching process.AFM images confirm that very small nanostructure features with average size of 80 nm can be obtained for p-n silicon in the photochemical etching process. Energy band diagrams of the three etching processes; Photochemical (PC), Electrochemical (EC) and Photoelectrochemical (PEC) provide good knowledge of the photogenerated/injected holes affecting the nanostructured surface formation. Image analysis software was used to examine the microstructuredsilicon surface produced by pulsed Nd:YAG laser. The thermal distribution profile showed that the surface temperature rises to about 2000 °C when a short laser pulse of 0.6 ms and high laser energy of 1 J were used. The surface and sub-surface temperature were estimated using COMSOL multiphysics software.

A new approach of pH-IEGFET sensor based on the surface modification of macro porous silicon with palladium nanoparticles

This work investigates the effect of the Palladium nanoparticles (PdNPs) on the characteristics and pH sensitivity of an interdigitated electrode extended-gate field-effect transistor (pH-IEGFET) sensors based on the bare n-type macro porous Si (n-macro PSi) layer. The synthesized bare porous layer was fabricated by photo electrochemical etching process of n-type (100) using short-wavelength 410 nm and intensive laser power density 80 mW/cm2. The surface morphology of n-macro PSi was modified by inserting PdNPs to form PdNPs/n-macro PSi hetero structure layers via simple and fast immersing process in PdCl2 solution for about 14 min and 20 min by the ion reduction process. The fabricated sensors have been verified in the range of pH from 3 to 11 at the ambient temperature. Specific features of n-macro PSi and hybrid structure were investigated using a scanning electron microscope, energy dispersive x-ray spectroscopy (EDX) analysis and x-ray diffraction. It was found that the morphology and the size of the deposited PdNPs intensely influence on the PdNPs/ n-macro PSi hetero structure pH-IEGFET sensor. The efficient pH sensing process was obtained for n-macro PSi pH sensor with the lowest size of PdNPs deposited on the external walls of the n-macro PSi pores. Significant enhancement of sensitivity of about 42.89 mV/pH and linearity of 0.9948 was achieved, compared with the bare n-macro PSi pH sensor having a sensitivity of 25.12 mV/pH and linearity of 0.9392. This sensitivity enhancement is due to the additional specific surface area of PdNPs which causes improved it.

Improvement Silicon Nanostructured Surface by Laser Induced Etching Process

Surface reconstruction of silicon using lasers could be utilized to produce silicon nanostructures of various features. Electrochemical and photoelectrochemical etching processes of silicon were employed to synthesize nanostructured surface. Effects of current densities 5, 10 and 20 mA/cm2 on the surface features were examined. It is found that the surface porosity and layer thickness increase with the current density. Moreover, large surface area of 410 m2/cm3 can be achieved when laser power density 0f 0.6 W/cm2 was used during the etching process. Optimum operating conditions were found to achieve better silicon nanostructured surface features. The surface roughness can be reduced to 8.3 nm using laser beam of 650 nm irradiated the silicon surface during the photoelectrochemical etching process. The surface morphology of the nanostructured silicon surface using SEM and AFM could give rich details about the surface. Silver nanoparticles of 10 – 20 nm was embedded at the nanostructured silicon surface by LIFT process to reduce the surface resistance and maintain the large surface area. This technique enables silicon nanostructures to be efficiently used in many optoelectronic applications.

Optimizing of Gold Nanoparticles on Porous Silicon Morphologies for a Sensitive Carbon Monoxide Gas Sensor Device

A set of carbon monoxide (CO) gas sensors based on porous silicon (PSi)/gold nanoparticle (AuNP) hetro structures were fabricated. Different forms of PSi surface morphologies were studied as a substrate for growth of AuNPs. Simple dipping process of PSi in hydrogen tetrachloroaurate (III) solution (HAuCl4) at fixed concentrations of 10−2 M/3.5 HF was used to synthesize AuNPs. The n-type PSi was equipped through photo-electrochemical etching process at current density value of 10 mA/cm2 under illumination condition of 530-nm wavelength and laser illumination intensity of 20 to 80 mW/cm2. Three different forms of PSi morphology, meso, macro, and double layers with pore shapes and sizes, were prepared. The structural and surface morphology properties of PSi-based substrate before and after deposition of AuNPs were investigated through studying of scanning electron microscopy (SEM), photoluminescence (PL), and X-ray diffraction (XRD). The electrical property (J-V) was carried out in primary vacuum and CO at low pressure. The results show that PSi surface morphologies strongly influenced the AuNP sizes and hence the sensor performance. It was found that decrease the AuNP sizes could be occasioned in high and fast current response.

Photoelectrochemical Properties of p- and n- Type 4H-SiC Epilayers: Doping Concentration Dependence and Dopant Selectivity

Exceptional chemical stability resulting from a large bandgap and low-lying valence band edge narrows the wet-etching based micromachining choices of the covalently bonded electronic and photonic device material, SiC, to mainly photoelectrochemical (PEC) dissolution. The PEC etching process has an anisotropic nature with the accompanying advantages of dopant, bandgap, and spatial selectivity, light intensity dependence, reduced ion damage, and the ability to undercut heterostructures. For the first time, a comprehensive photogenerated minority carrier assisted etching investigation was carried out on Si polar surface of high-quality (micropipe density <1 cm-2) p- and n- type (0001) 4H-SiC epilayers having intentional or unintentional doping densities in the 1014–1018 cm-3 range. Cyclic voltametry and chronoamperometry studies under a parallel supra-bandgap (~320 nm) light illumination with varying intensities (≤0.85 Wcm-2) in a highly basic etching medium (1 wt% KOH solution, pH ~12) revealed the dependence of etch voltage and etch rate (~30–90 nm/min) on type and concentration of doping. In addition, a mutually exclusive etch voltage window (~±0.3–0.5 V versus saturated calomel electrode) was established for both types of conductivities in the diffusion-limited regime. Results to be presented can provide key insight in design and fabrication for higher performance three dimensional SiC homojunctions for various applications including photonic crystal cavities.

Synthesis and characterization of porous silicon gas sensors

In this work, photo-electrochemical etching process of n-type Silicon of resistivity(10 Ω.cm) and (100) orientation, using two illumination sources IR and violet wavelength in HF acid have been used to produce PSi gas detection device. The fabrication process was carried out at a fixed etching current density of 25mA/cm2 and at different etching time (5, 10, 15 and 20) min and (8, 16, 24, and 30) min. Two configurations of gas sensor configuration planer and sandwich have been made and investigated. The morphological properties have been studied using SEM,the FTIR measurement show that the (Si-Hx) and (Si-O-Si) absorption peak were increases with increasing etching time,and Photoluminescence properties of PSi layer show decrease in the peak of PL peak toward the violet shift. The gas detection process is made on the CO2 gas at different operating temperature and fixed gas concentration. In the planner structure, the gas sensing was measured through, the change in the resistance readout as a function to the exposure time, while for sandwich structure J-V characteristic have been made to determine the sensitivity.

High-aspect ratio micro- and nanostructures enabled by photo-electrochemical etching for sensing and energy harvesting applications

Photo-electrochemical (PEC) etching can produce high-aspect ratio features, such as pillars and holes, with high anisotropy and selectivity, while avoiding the surface and sidewall damage caused by traditional deep reactive ion etching (DRIE) or inductively coupled plasma (ICP) RIE. Plasma-based techniques lead to the formation of dangling bonds, surface traps, carrier leakage paths, and recombination centers. In pursuit of effective PEC etching, we demonstrate an optical system using long wavelength (λ = 975 nm) infra-red (IR) illumination from a high-power laser (1–10 W) to control the PEC etching process in n-type silicon. The silicon wafer surface was patterned with notches through a lithography process and KOH etching. Then, PEC etching was introduced by illuminating the backside of the silicon wafer to enhance depth, resulting in high-aspect ratio structures. The effect of the PEC etching process was optimized by varying light intensities and electrolyte concentrations. This work was focused on determining and optimizing this PEC etching technique on silicon, with the goal of expanding the method to a variety of materials including GaN and SiC that are used in designing optoelectronic and electronic devices, sensors and energy harvesting devices.

Stress and thermal characterization of 4H-SiC microelectromechanical structures

In this letter, the potential of single crystalline 4H-polytype silicon carbide (4H-SiC) based microelectromechanical structures as resistance thermometer for high temperature sensing were explored. A dopant-selective photoelectrochemical etching process was applied to release the sensing element – suspended microstructures on 4H-SiC substrate. Residual stress and stress gradient in the microstructure before and after release was examined by micro-Raman spectroscopy. Electrical resistance of the suspended microstructures at different temperatures were characterized and analyzed by a temperature-dependent electron mobility model.

Quantum Confinement of Integrated Pulse Electrochemical Etching of Porous Silicon for Metal Semiconductor Metal Photodetector

Porous silicon (PS) was successfully synthesized via novel integrated pulsed electrochemical etching of an n-type (100) silicon (Si) substrate under various condition. The PS was etched using hydrofluoric acid (HF) based solution and the porosity was optimized by introducing electroless chemical etching process prior to photo electrochemical (PEC) anodization. In the electroless etching, a delay time (TD) of 2 min was applied. After that a cycle time (T) and pause time () of pulsed current were supplied throughout the 30 min PEC etching process. As grown Si and PS through conventional direct current (DC) anodization were also included for comparison. The result obtained showed that applying delay time helps to improve the uniformity and density of the porous structures. AFM indicated that the roughness of the Si increases as the dissolution of the Si occurred. Raman spectroscopy showed that an improvement in the crystalline quality of PS under pulse etching method compared to DC method indicated by the reduction of full width at half maximum (FWHM). A broad visible photoluminescence (PL) was observed from green to red with blue shift as nanocrystallite size decreases which constituted quantum confinement effect from the PS structures. Nickel (Ni) finger contact was deposited onto the PS to form metal semiconductor metal (MSM) photodetector. Ni/PS MSM photodetector by pulse method exhibited higher gain (2 times) compared to conventional Si device at 5 V bias.

Influence of pH on the Quantum-Size-Controlled Photoelectrochemical Etching of Epitaxial InGaN Quantum Dots

Illumination by a narrow-band laser has been shown to enable photoelectrochemical (PEC) etching of InGaN thin films into quantum dots with sizes controlled by the laser wavelength. Here, we investigate and elucidate the influence of solution pH on such quantum-size-controlled PEC etch process. We find that although a pH above 5 is often used for PEC etching of GaN-based materials, oxides (In2O3 and/or Ga2O3) form which interfere with quantum dot formation. At pH below 3, however, oxide-free QDs with self-terminated sizes can be successfully realized.

Porous Silicon Morphology: Photo-Electrochemically Etched by Different Laser Wavelengths

Porous silicon (PS) has become the focus of attention in upgrading silicon for optoelectronics. In this work, various structures were produced depending on the formation parameters by photo-electrochemical etching (PECE) process of n- and p-type silicon wafer at different time durations (5–90 mins) and different current densities (5, 15, and 20 mA/cm2) for each set of time durations. Diode lasers of 405 nm, 473 nm, and 532 nm wavelengths, each 50 mW power, were used to illuminate the surface of the samples during the etching process. The results showed that controlled porous layers were achieved by using blue laser, giving uniform structure which can make it possible to dispense with expensive methods of patterning the silicon.