2019年7月17日星期三

Detection of spin-states in Mn-doped gallium arsenide films

We show that isolated magnetic dipoles centred at the position of manganese impurities in a gallium arsenide lattice lead to spin polarized states in the bandgap of the III–V semiconductor. Spectroscopy simulations with a tungsten tip agree well with experimental data; in this case, no difference can be observed for the two magnetic groundstates. But if the signal is read with a magnetic iron tip, it changes by a factor of up to 20, depending on the magnetic orientation of the Mn atom.



Source:IOPscience

For more information, please visit our website: www.semiconductorwafers.net,

2019年7月9日星期二

An automatic plotting system for the electrochemical characterization of n-type gallium arsenide

A system is described for the automatic plotting of the electrochemical voltage-log current characteristics of gallium arsenide samples. The plots are in a convenient form for analysis, which allows the electron concentration, and minority carrier diffusion length, of n-type samples to be estimated. The technique permits electrochemical stripping and measurements to be performed in situ in the same electrolytic cell, so that depth profiles of measured parameters may readily be obtained.



Source:IOPscience

For more information, please visit our website: www.semiconductorwafers.net,

2019年6月20日星期四

Thermally stimulated conductivity in semi-insulating gallium arsenide at low and intermediate electric fields

A method of producing and investigating trapping effects in semiconductors and insulators has been devised which uses the variation of applied electric field strength during the measurement of thermally stimulated conductivity. Experiments on chromium-, oxygen-, and iron-doped semi-insulating gallium arsenide crystals have shown that a change in the electric field may shift existing peaks, excite new peaks, or induce the enhancement, broadening, narrowing or quenching of the existing peaks in the thermally stimulated conductivity spectrum. At relatively high fields, current instabilities were sometimes observed in the region of a peak. It is suggested that these changes are caused mainly by the modification of the capture cross section of the traps.



Source:IOPscience

For more information, please visit our website: www.semiconductorwafers.net,

2019年6月14日星期五

Stoichiometric Change in Gallium Arsenide after Laser-Induced Thermochemical Etching

Gallium arsenide surfaces after laser-induced thermochemical etching in a CCl4 atmosphere were investigated by Auger electron spectroscopy. The laser-etched surfaces were deficient in arsenic and the excess gallium was found in a depth down to 20 nm from the etched surface for a laser power from 0.3 to 0.5 W at a scan speed of 6-30 µm/s. The thickness of the arsenic-deficient layers depended on both laser power and scan speed.



Source:IOPscience

For more information, please visit our website: www.semiconductorwafers.net,

2019年6月5日星期三

Non-destructive measurement of carrier concentration in epitaxial gallium arsenide

Infra-red reflection measurements have been performed on specimens of n-type epitaxial gallium arsenide in the spectral range 10-200 cm−1. From measurements of the wavelength position of the plasma absorption edge the carrier concentration in these samples has been determined, using a calibration curve produced by measurements on bulk single-crystal samples of known concentration - between 1015 and 1017 carriers/cm3.



Source:IOPscience

For more information, please visit our website: www.semiconductorwafers.net,

2019年5月28日星期二

The influence of the chemical and physical component of the plasma etching of the surface of gallium arsenide on the etching rate in the chloride plasma of the combined discharge

In this paper, experimental studies were carried out on the formation of a microrelief on the surface of gallium arsenide substrates. The surface was modified by the method of plasma etching. Etching was carried out in a medium of chloride gas. In the work, the etching rates of the surface of gallium arsenide depend on the power of the inductively coupled plasma source. The etching rate of gallium arsenide was 28.2 nm / min, 24.9 nm / min, 27.8 nm / min, at inductively coupled plasma power values of 200 W, 400 W and 600 W. In the same work, the patterns of etching rate of gallium arsenide surface Taking into account the capacity of the capacitive plasma and the voltage of the shift. The etching rate of gallium arsenide was 516.7 nm / min, 559.5 nm / min, 603.3 nm / min, with capacitive plasma power values of 10 W, 35 W and 70 W, respectively. These results can be used to form a modified surface for the subsequent epitaxial growth of quantum dots based on gallium arsenide.


Source:IOPscience

For more information, please visit our website: www.semiconductorwafers.net,

2019年5月23日星期四

A technique for the growth of single crystal films of zinc sulphide on (100) gallium arsenide by radio frequency sputtering

Thin films of single crystal cubic zinc sulphide has been grown on (100) oriented gallium arsenide substrates by a radio frequency sputtering technique. The sputtering system is of novel design, being constructed to UHV standards and capable of producing oil-free ultraclean conditions during the sputtering process. A balanced RF oscillator drives the water cooled disc and annulus electrodes to which sintered powder ZnS targets are bonded with an indium-gallium eutectic. Highly ordered films are grown at rates of up to 100 nm h-1 at temperatures between 250 degrees C and 300 degrees C.


Source:IOPscience

For more information, please visit our website: www.semiconductorwafers.net,