Dry Etching Characteristics of Amorphous Indium-Gallium-Zinc-Oxide Thin Films

Amorphous indium-gallium-zinc-oxide （a-IGZO） thin-film transistor （TFT） backplane technology is the best candidate for flat panel displays （FPDs）. In this paper, a-IGZO TFT structures are described. The effects of etch parameters （rf power, dc-bias voltage and gas pressure） on the etch rate and etch profile are discussed. Three kinds of gas mixtures are compared in the dry etching process of a-IGZO thin films. Lastly, three problems are pointed out that need to be addressed in the dry etching process of a-IGZO TFTs.

Alkali and Plasma-Treated Guadua angustifolia Bamboo Fibers:A Study on Reinforcement Potential for Polymeric Matrices

This study focuses on treating Guadua angustifolia bamboo fibers to enhance their properties for reinforcement applications in composite materials.Chemical(alkali)and physical(dry etching plasma)treatments were used separately to augment compatibility of Guadua angustifolia fibers with various composite matrices.The influence of these treatments on the fibers’performance,chemical composition,and surface morphology were analyzed.Statistical analysis indicated that alkali treatments reduced the tensile modulus of elasticity and strength of fibers by up to 40%and 20%,respectively,whereas plasma treatments maintain the fibers’mechanical performance.FTIR spectroscopy revealed significant alterations in chemical composition due to alkali treatments,while plasma-treated fibers showed minimal changes.Surface examination through Scanning Electron Microscopy(SEM)revealed post-treatment modifications in both cases;alkali treatments served as a cleanser,eliminating lignin and hemicellulose from the fiber surface,whereas plasma treatments also produce rough surfaces.These results validate the impact of the treatments on the fiber mechanical performance,which opens up possibilities for using Guadua angustifolia fibers as an alternative reinforcement in composite manufacturing.

High-Power and High-Efficiency 650nm-Band AlGaInP Visible Laser Diodes Fabricated by Ion Beam Etching

High power and high-slope efficiency 650nm band real-refractive-index ridge w aveguide AlGaInP laser diodes with compressive strained MQW active layer are for med by pure Ar ion beam etching process.Symmetric laser mesas with high perpendi cularity,which are impossible to obtain by traditional wet etching method due to the use of a 15°-misoriented substrate,are obtained by this dry etching metho d.Laser diodes with 4μm wide,600μm long and 10%/90% coat are fabricated.Th e typical threshold current of these devices is 46mA at room temperature,and a s table fundamental-mode operation over 40mW is obtained.Very high slope efficien cy of 1.4W/A at 10mW and 1.1W/A at 40mW are realized.

ICP dry etching ITO to improve the performance of GaN-based LEDs

In order to improve the light efficiency of the conventional GaN-based light-emitting diodes （LEDs）, the indium tin oxide （ITO） film is introduced as the current spreading layer and the light anti-reflecting layer on the p-GaN surface. There is a big problem with the ITO thin film＇s corrosion during the electrode preparation. In this paper, at least, the edge of the ITO film was lateral corroded 3.5μm width, i.e. 6.43%-1/3 of ITO film＇s area. An optimized simple process, i.e. inductively couple plasma （ICP）, was introduced to solve this problem. The ICP process not only prevented the ITO film from lateral corrosion, but also improved the LED＇s light intensity and device performance. The edge of the ITO film by ICP dry etching is steep, and the areas of ITO film are whole. Compared with the chip by wet etching, the areas of light emission increase by 6.43% at least and the chip＇s lop values increase by 45.9% at most.

Strain analysis of free-standing strained silicon-on-insulator nanomembrane

Based on the ultra-thin strained silicon-on-insulator（s SOI） technology, by creatively using a hydrofluoric acid（HF）vapor corrosion system to dry etch the Si O2 layer, a large area of suspended strained silicon（s Si） nanomembrane with uniform strain distribution is fabricated. The strain state in the implemented nanomembrane is comprehensively analyzed by using an UV-Raman spectrometer with different laser powers. The results show that the inherent strain is preserved while there are artificial Raman shifts induced by the heat effect, which is proportional to the laser power. The suspended s SOI nanomembrane will be an important material for future novel high-performance devices.

Dry etching of new phase-change material Al_(1.3)Sb_3Te in CF_4/Ar plasma

The dry etching characteristic of AlSbTe film was investigated by using a CF/Ar gas mixture.The experimental control parameters were gas flow rate into the chamber,CF/Ar ratio,the Oaddition,the chamber background pressure,and the incident RF power applied to the lower electrode.The total flow rate was 50 sccm and the behavior of etch rate of AlSbTe thin films was investigated as a function of the CF/Ar ratio,the Oaddition,the chamber background pressure,and the incident RF power.Then the parameters were optimized.The fast etch rate was up to 70.8 nm/min and a smooth surface was achieved using optimized etching parameters of CFconcentration of 4%,power of 300 W and pressure of 80 mTorr.

Highly controllable ICP etching of GaAs based materials for grating fabrication

Highly controllable ICP etching of GaAs based materials with SiCl;/Ar plasma is investigated.A slow etching rate of 13 nm/min was achieved with RFl = 10 W,RF2 = 20 W and a high ratio of Ar to SiCl;flow.First order gratings with 25 nm depth and 140 nm period were fabricated with the optimal parameters.AFM analysis indicated that the RMS roughness over a 10 x 10μm;area was 0.3 nm,which is smooth enough to regrow high quality materials for devices.

Post-Gate Process Annealing Effects of Recessed AlGaN/GaN HEMTs

This paper focuses on how to reduce the gate leakage current caused by plasma dry etching. X-ray photoelectron spectroscopy （XPS） is employed to measure the AlGaN surface before and after etching. N vacancies are introduced, which cause that gate currents are not dominated by the thermal electron emission mechanism. N vacancies enhance the tunneling effect and reduce the Schottky barrier height as n-type doped in the etched AIGaN surface.A post-gate process for AlGaN/GaN HEMTs,annealing at 400℃ in a nitrogen ambient for 10min is introduced. After annealing, Ni atoms of gate metal reacted with Ga atoms of AlGaN, and N vacancies were reduced. The reverse leakage decreased by three orders of magnitude,the forward turn-on voltage increased and the ideality factor reduced from 3.07 to 2.08.

GaN metal-oxide-semiconductor field-effect transistors on AIGaN/GaN heterostructure with recessed gate

GaN metal-oxide-semiconductor field-effect transistors （MOSFETs） on AIGaN/GaN heterostructure with a recess gate were fabricated and characterized. The device showed good pinch-off characteristics and a maximum field-effect mobility of 145.2 cm2.V-1.s-1. The effects of etching gas of CI2 and SiCI4 were investigated in the gate recess process. SiCI4-etched devices showed higher channel mobility and lower threshold voltage. Atomic force microscope measurement was done to investigate the etching profile with different etching protection mask. Compared with photoresist, SiO2- masked sample showed lower surface roughness and better profile with stepper sidewall and weaker trenching effect resulting in higher channel mobility in the MOSFET.