Services
- Current noise measurements
The current flowing through the contacts of a device is noisy due to the physical processes of generating current: discretization of carriers, temperature, processes of generation and recombination of carriers, etc.. Noise can obscure or suppress the signal from an electronic device. It may not be avoided, but can be characterized and maintained as low as possible. In our laboratory we perform noise measurements of a sample in the range of 0 to 100 kHz for any temperature between 77 and 300 K.
- ECV Profiler
The system allows the measurement of free carrier density in function of the thickness (a profile of the doping) in semiconductor samples. The measured area is a circle of 3.5 mm or 1 mm diameter. In the presence of a doped substrate the minimum sample size is 0.5X0.5 cm (back contact) in the case of semi-insulating substrate the minimum sample size is 1.5X0.5 cm (front contact).
- Growth
Production of III-V semiconductor thin films or heterostructures like In1-x-yAlxGayAs, GaAs, InP, InxGa1-xAsyP1-y with control of the alloy composition in percent scale and also with control of the thickness from 1 nanometer to 3 micrometers in atomic monolayer scale. It is also possible to produce III-V semiconductor quantum dots with nanometer dimensions and planar density of 1010cm-2 on the surface of the aforementioned thin films.
- Hall effect measurement
This system allows the measurement of resistivity, carrier concentration and mobility at room temperature and at 77K in semiconductor samples (the conductive thickness of the sample is a necessary data). The geometry of the electrical contacts can be Van der Pauw or Bar / Bridge - like. The typical size of the measured sample is 0.5X0.5cm.
- In situ X-ray powder diffraction
X-ray powder diffractometer, with Theta/Theta arrangement, acquiring patterns between 0.5o and 140o2 Theta using a linear detector LynxEye coupled with reaction, low and high temperature chambers, capable to operate with different gases and temperatures between – 180oC and 1550oC.
- I-V curve measurements
In our laboratory we perform this measurement in the voltage ranges of ± 20 and ± 2 VDC and currents up to 1 picoampere (1x10-12 A). This measurement can be performed at any temperature between 10 and 300 K.
- Photoluminescence
The spectroscopy measurements can be performed for any type of sample whose spectral response is on range that the sensor is capable of analyzing (from 500 to 2500nm for measurements with Ge and InGaAs sensors; 2500 a 25000nm for measurements performed with the FTIR). Among the types of samples we can have binary semiconductors (GaAs and InP), ternary (AlGaAs, InGaAs, InAlAs …), quaternary (InGaAsP, InAlAsP …), quantum wells and quantum dots.
- Processing of III-V semiconductor samples
In general, the standard of a semiconductor device structure consists of an active region surrounded by two layers of doped material, which act as the contact layers. Starting from the grown samples, the fabrication of the devices is the formation of mesas to set the physical dimensions of the devices, and the deposition of metal contacts that will allow the electrical and optical tests. The formation of electrical connections is performed by a wirebonder with gold threads 25 microns thick. In our laboratory we perform photolithographic processes by photolithography, chemical etching, metallization for making metal contacts and wirebonder for electrical connections.
- Profilometry
Surface profile measurement using a probe. It has a vertical resolution of 5 ? (K? mode) or 5 nm (µm mode) and a horizontal resolution of 400 ?. The maximum horizontal range is 10 mm and vertical range is 160 K? (K? mode) or 160 µm (µm mode).
- Small Angle X-Ray Scattering
Small Angle X-Ray Scattering of amorphous and polycrystalline materials, as powder, liquid, or thin films. It allows to determine the size distribution of nanoparticles.
- Thin film diffraction
We are capable to do x-ray diffraction of polycrystalline thin film using constant grazing incidence angles between 0,2 to 8 degrees to limite the maximum x-ray penetration depth. The detector scanning is independent of the grazing incidence. It is also possible to use the Eulerian goniometer to measure thin film strain (stress).
- X Ray Diffraction
High Resolution X-Ray (HRXR) diffraction for semiconductor thin films using a Rocking Curve measurement with 1 arcsecond angular resolution and up till 10000 arcsecond range.
- X-ray Powder diffraction
X-ray powder diffractometer, with Theta/Theta arrangement, capable to collect patterns between 0.5oand 140o 2 Theta using a linear detector LynxEye and a typical step of 0.02o.