A miniature double plasma jet source driven at microwave frequencies (∼2.45 GHz) was developed and analyzed. The source consists of a copper resonator (screened within an aluminum housing) that excites plasma simultaneously in two alumina tubes of 5 mm internal diameter. Field and plasma simulations were performed using the software Comsol. Assuming a homogeneous electron distribution we calculate the plasma impedance as a function of its conductivity. The electron density and the plasma conductivity are estimated as a function of the absorbed power in plasma for argon and oxygen. Experimentally it was shown that the microwave energy is coupled into oxygen plasma with an efficiency of >85% and into argon plasma with ∼30%. The source efficiently produces atomic oxygen and nitrogen as is demonstrated by plasma-enhanced atomic layer deposition. Finally, the time evolution during ignition, the transition from low efficient capacitive to highly efficient inductive coupling, the free electron distribution as a function of time and other parameters are analyzed.
Articles you may be interested inInGaAs metal-semiconductor-metal photodetectors with engineered Schottky barrier heights Two-dimensional device modeling and analysis of GaInAs metal-semiconductor-metal photodiode structures High-speed GaAs metal-semiconductor-metal photodetectors with recessed metal electrodes Picosecond dynamic response of nanoscale low-temperature grown GaAs metal-semiconductor-metal photodetectors Appl.We report on passivation and antireflection coating of InP/InGaAs metal-semiconductor-metal photodetectors by low-temperature deposited silicon dioxide. The passivating performance of silicon dioxide films applied by nonreactive radio frequency magnetron sputtering and remote plasma enhanced chemical vapor deposition are comparatively investigated. Different wet chemical treatments of the InP surface prior to deposition including sulfur passivation are performed and their influences on the device performance are presented. Under optimized deposition conditions and pretreatments, both processes result in a stable and reproducible surface passivation as reflected by a drastic reduction of excessive leakage currents and photocurrent gain. The improvement of the device characteristics due to the silicon dioxide coating is attributed to a substantial lowering of the density of interface states at the insulator-InP interface as compared to nonpassivated devices.
We have investigated t h e influence of dinerent acceptor diffusion methods on the diffusion length of the minority carriers (electrons) in InGaAsllnP samples. Zn and Cd were diffused into InGaAs separately or simultaneously. The diffusion length was estimated by fitting numerical calculations to the measured spectral response of pn structures with different junction depths. The results support the assumption of t h e creation of crystal defects during the diffusion. which enhance recombination processes and make the carrier lifetime small. Consequently, the diffusion length does not achieve the magnitude that should be possible theoretically. The values we estimated were L, = 0.44.6pm at p-doping levels of about 2 4 x 10'ecm-3. T h e experimental results show that the diffusion length does not depend significantly on the diffusing species
The room‐temperature luminescence decay of nitrogen and tellurium‐doped VPE‐GaP epitaxial layers is investigated in dependence on the exciting photon energy hν. For increasing excitation energies a strong non‐exponential decay behaviour is observed which is unambiguously associated with surface recombination processes. Their influence on the time behaviour of the optically excited minority carrier system is described by a simple theoretical model. Using this model the surface recombination velocity s is determined in dependence on different chemical surface preparation techniques. Typical values of s are in the range 2 × 103 to 2 × 105 cm s−1.
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