- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Thermal atomic layer etching: Mechanism, materials and prospects
摘要： In the semiconductors and related industries, the fabrication of nanostructures and nanopatterns has become progressive demand for achieving near-atomic accuracy and selectivity in etching different materials, particularly in ultra-thin gate dielectrics and ultra-thin channels used in field-effect transistors and other nanodevices below 10 nm scale. Atomic layer etching (ALE) is a novel technique for removing thin layers of material using sequential and self-limiting reactions. Different from most ALE processes using plasma-enhanced or other energetic particles-enhanced surface reactions, thermal ALE realizes isotropic atomic-level etch control based on sequential thermal-drive reaction steps that are self-terminating and self-saturating. Thermal ALE can be viewed as the reverse of atomic layer deposition (ALD), both of which define the atomic layer removal and growth steps required for advanced semiconductor fabrication. In this review, we focus on the concept and basic characteristics of the thermal ALE in comparison with ALD. Several typical thermal ALE mechanisms including fluorination and ligand-exchange, conversion-etch, oxidation and fluorination reactions are intensively introduced. The pros and cons of thermal ALE, plasma ALE, and traditional plasma etching are compared. Some representative materials and their typical thermal ALE processes are summarized. Finally, the outlook and challenges of thermal ALE are addressed.
关键词： Thermal atomic layer etching,Reaction mechanism,Atomic-scale precision,Atomic layer deposition,Self-limiting
更新于2025-09-23 15:22:29
-
Analysis and design of a multi-channel constant current LED driver based on DC current bus distributed power system structure
摘要： In this paper, we have extensively investigated the impact of anode recess on the reverse leakage current, forward voltage (VF), and dynamic characteristics of Au-free AlGaN/GaN Schottky barrier diodes with a gated edge termination (GET-SBDs) on 200-mm silicon substrates. By increasing the number of atomic layer etching (ALE) cycles for anode recessing, we have found that: 1) the reverse leakage current is strongly suppressed due to a better electrostatic control for pinching off the channel in the GET region; a median leakage current of ～1 nA/mm and an ION/IOFF ratio higher than 108 have been achieved in GET-SBDs with six ALE cycles; 2) the forward voltage (～1.3 V) is almost independent of the ALE cycles, taking into account its statistical distribution across the wafers; 3) when the remaining AlGaN barrier starts to be very thin (in the case of six ALE cycles), a spread of the ON-resistance, mainly attributed to the GET region, can occur due to the dif?cult control of the remaining AlGaN thickness and surface quality; and 4) the dynamic forward voltage of GET-SBDs shows a mild dependence on the ALE process in pulsed I–V characterization, and a more ALE-dependent dynamic ON-resistance is observed.
关键词： atomic layer etching (ALE),200-mm,leakage,metal–insulator–semiconductor high-electron mobility transistor (MISHEMT),GET-SBD,diode,AlGaN/GaN
更新于2025-09-23 15:21:01
-
[IEEE 2019 IEEE International Conference on Mechatronics and Automation (ICMA) - Tianjin, China (2019.8.4-2019.8.7)] 2019 IEEE International Conference on Mechatronics and Automation (ICMA) - Optimization of Spectroscope Parameters for Single-beam Pulsed Laser Scanning Circumferential Detection System
摘要： In this paper, we have extensively investigated the impact of anode recess on the reverse leakage current, forward voltage (VF), and dynamic characteristics of Au-free AlGaN/GaN Schottky barrier diodes with a gated edge termination (GET-SBDs) on 200-mm silicon substrates. By increasing the number of atomic layer etching (ALE) cycles for anode recessing, we have found that: 1) the reverse leakage current is strongly suppressed due to a better electrostatic control for pinching off the channel in the GET region; a median leakage current of ～1 nA/mm and an ION/IOFF ratio higher than 108 have been achieved in GET-SBDs with six ALE cycles; 2) the forward voltage (～1.3 V) is almost independent of the ALE cycles, taking into account its statistical distribution across the wafers; 3) when the remaining AlGaN barrier starts to be very thin (in the case of six ALE cycles), a spread of the ON-resistance, mainly attributed to the GET region, can occur due to the difficult control of the remaining AlGaN thickness and surface quality; and 4) the dynamic forward voltage of GET-SBDs shows a mild dependence on the ALE process in pulsed I–V characterization, and a more ALE-dependent dynamic ON-resistance is observed.
关键词： leakage,diode,AlGaN/GaN,GET-SBD,metal–insulator–semiconductor high-electron mobility transistor (MISHEMT),200-mm,atomic layer etching (ALE)
更新于2025-09-23 15:19:57
-
[IEEE 2019 International Conference on Mechatronics, Robotics and Systems Engineering (MoRSE) - Bali, Indonesia (2019.12.4-2019.12.6)] 2019 International Conference on Mechatronics, Robotics and Systems Engineering (MoRSE) - Bottled Water Identification & Fraud Detection Using Spectroscopy & Convolutional Neural Network
摘要： In this paper, we have extensively investigated the impact of anode recess on the reverse leakage current, forward voltage (VF), and dynamic characteristics of Au-free AlGaN/GaN Schottky barrier diodes with a gated edge termination (GET-SBDs) on 200-mm silicon substrates. By increasing the number of atomic layer etching (ALE) cycles for anode recessing, we have found that: 1) the reverse leakage current is strongly suppressed due to a better electrostatic control for pinching off the channel in the GET region; a median leakage current of ～1 nA/mm and an ION/IOFF ratio higher than 108 have been achieved in GET-SBDs with six ALE cycles; 2) the forward voltage (～1.3 V) is almost independent of the ALE cycles, taking into account its statistical distribution across the wafers; 3) when the remaining AlGaN barrier starts to be very thin (in the case of six ALE cycles), a spread of the ON-resistance, mainly attributed to the GET region, can occur due to the dif?cult control of the remaining AlGaN thickness and surface quality; and 4) the dynamic forward voltage of GET-SBDs shows a mild dependence on the ALE process in pulsed I–V characterization, and a more ALE-dependent dynamic ON-resistance is observed.
关键词： atomic layer etching (ALE),200-mm,leakage,metal–insulator–semiconductor high-electron mobility transistor (MISHEMT),GET-SBD,diode,AlGaN/GaN
更新于2025-09-19 17:13:59
-
Low damage patterning of In <sub/>0.53</sub> Ga <sub/>0.47</sub> As film for its integration as n-channel in a fin metal oxide semiconductor field effect transistor architecture
摘要： One of the challenges of InGaAs integration as a channel in a fin field effect transistor architecture is the patterning of the III–V fin with nanometer scale definition, vertical sidewalls, and undamaged surfaces. In this work, the authors propose a two-step process to etch anisotropically and with minimal damage thin layers of InGaAs material. The first step of the process aims to modify the InGaAs surface on a well-defined thickness with limited sputtering by implanting light ions generated by a low pressure He/O2 plasma. The depth of the material modification is well controlled by the ion energy and saturates with process time, giving to this step a self-limited behavior. The second step uses aqueous HF solution to remove the modified oxidized InGaAs layer with infinite selectivity over the nonmodified InGaAs layer. The repetition of cycles of the two-step process was applied to etch the thin film of InGaAs as well as pattern using a SiN hard mask. Blanket experiments show that each cycle of the two-step process allows to remove a fixed and reproducible InGaAs thickness of 5.7 nm, while blanket SiN films are not consumed. After the process, the InGaAs surface roughness is kept intact, but the surface stoichiometry is slightly degraded with Arsenic enrichment because of the wet chemical reactions between the III-As semiconductors and the acids. The results on the pattern show that it is possible to transfer the SiN hard mask into the InGaAs layer using cycles of the two-step process with a reproducible consumed InGaAs thickness at each cycle and low sidewalls surface damage. However, the process leads to tapered InGaAs profile because of the lateral consumption of the SiN hard mask due to preferential sputtering at grazing incidence angle.
关键词： FinFET,atomic layer etching,stoichiometry,plasma etching,InGaAs,surface damage
更新于2025-09-10 09:29:36
-
Thermal Atomic Layer Etching of Silicon Using O2, HF and Al(CH3)3 as the Reactants
摘要： The thermal atomic layer etching (ALE) of silicon was performed using O2, HF and Al(CH3)3 as the reactants at temperatures from 225-290°C. This thermal etching process is based on Si oxidation using O2 and conversion of SiO2 to Al2O3 using trimethylaluminum (TMA). Al2O3 is then fluorinated by HF to produce AlF3 prior to removal of AlF3 by a ligand-exchange reaction with TMA. Thermal Si ALE was studied using silicon-on-insulator (SOI) wafers. In situ spectroscopic ellipsometry was employed to monitor simultaneously both the thickness of the top SiO2 layer and the underlying silicon film during Si ALE. These studies observed that the silicon film thickness decreased linearly with the number of reaction cycles while the thickness of the SiO2 layer remained constant. Using an O2-HF-TMA exposure sequence, the Si ALE etch rate was 0.4 ?/cycle at 290°C. This etch rate was obtained using static reactant pressures of 250, 1.0 and 1.0 Torr, and exposure times of 10, 5 and 5 s, for O2, HF and TMA, respectively. The SiO2 thickness was 10-11 ? under these reaction conditions at 290°C. The Si ALE etch rate increased with O2 and TMA pressure before reaching a limiting etch rate at higher O2 and TMA pressures. The order of the reactants affected the Si etch rate. Changing the exposure sequence from O2-HF-TMA to O2-TMA-HF reduced the etch rate from 0.4 to 0.2 ?/cycle at 290°C. Lowering the etch temperature below 290oC also resulted in the reduction of the Si etch rate. Atomic force microscopy (AFM) measurements determined that the root-mean-squared (RMS) roughness of the surface was 2.0 ± 0.2 ? before and after the Si ALE using the optimum reaction conditions. Lowering the static O2 pressures below 250 Torr reduced the etch rate and also increased the RMS surface roughness. There was no evidence for any change in the Si ALE process for ultrathin Si films with thicknesses <100 ? in the quantum confinement regime. Thermal Si ALE should be useful for silicon applications in many areas including electronics, optoelectronics, thermoelectrics and photonics.
关键词： silicon,HF,thermal atomic layer etching,spectroscopic ellipsometry,Al(CH3)3,O2,atomic force microscopy
更新于2025-09-10 09:29:36
-
Atomic layer etching of chrome using ion beams
摘要： In this study, two Cr atomic layer etching (ALE) methods have been applied for the precise control of Cr etching. The first one involves O radical adsorption followed by Cl+ ion desorption (ALE with chemical ion desorption; chemical anisotropic ALE), and the second one involves Cl/O radical adsorption followed by Ar+ ion desorption (ALE with physical ion desorption; physical anisotropic ALE). Their effects on Cr etch characteristics were also investigated. For both the ALE methods, saturated Cr etch depth/cycle of 1.1 and 1.5 ? /cycle were obtained for the chemical and physical anisotropic ALE, respectively, while maintaining near-infinite etch selectivities with various Si-based materials like silicon, silicon dioxide, and silicon nitride. The ALE technique can be used to precisely control the thickness of materials, including metals such as Cr, without any surface damage.
关键词： etch selectivity,adsorption,atomic layer etching,x-ray photoelectron spectroscopy,ion beam,chrome
更新于2025-09-04 15:30:14