2016年9月26日星期一

Wafer-scale processing technology for monolithically integrated GaSb thermophotovoltaic device array on semi-insulating GaAs substrate

This paper presents the entire fabrication and processing steps necessary for wafer scale monolithic integration of series interconnected GaSb devices grown on semi-insulating GaAs substrates. A device array has been fabricated on complete 50 mm (2 inch) diameter wafer using standard photolithography, wet chemical selective etching, dielectric deposition and single-sided metallization. For proof of concept of the wafer-scale feasibility of this process, six large-area series interconnected GaSb p–n junction thermophotovoltaic cells with each cell consisting of 24 small-area devices have been fabricated and characterized for its electrical connectivity. The fabrication process presented in this paper can be used for optoelectronic and electronic device technologies based on GaSb and related antimonide based compound semiconductors.

Keywords:  wafer scale;  series interconnected GaSb devices;  semi-insulating GaAs substrates;  GaSb p–n junction thermophotovoltaic cells;  compound semiconductors

Source: iopscience

If you are more interesting in GaSb wafer, please send emails to us: sales@powerwaywafer.com and visit our website:www.powerwaywafer.com

2016年9月19日星期一

Temperature-dependent GaSb material parameters for reliable thermophotovoltaic cell modelling

GaSb photovoltaic cells are the most common choice for receivers in thermophotovoltaic (TPV) systems. Although nowadays their manufacturing technology is well established, a theoretical simulation frame for their modelling under real TPV operating conditions is still not fully developed. This is basically due to the lack of a reliable and accurate set of GaSb material parameters as input for the semiconductor simulation tools. Thorough GaSb TPV cell models are needed to understand the electro-optical behaviour of the cells and eventually are essential in improving their design. This work will try to go beyond this key issue, carefully analysing and reviewing some of the key parameters for GaSb. A complete set of material parameters, including revised values for the intrinsic concentration, the electron and hole mobilities and the absorption coefficient, is given based on extended reviews of previously published data. For the first time, estimations for their temperature dependences are introduced. Finally, GaSb TPV cells are manufactured and characterized inside a real TPV system prototype. The comparisons between the electrical measurements and the model theoretical predictions confirm the validity of the proposed set of GaSb material parameters and their temperature dependences.

Keywords:  GaSb photovoltaic cells ;  thermophotovoltaic (TPV) systems; GaSb material parameters;  GaSb TPV; 

Source: iopscience

If you are more interesting in GaSb wafer,please send emails to us:sales@powerwaywafer.com and visit our website: www.powerwaywafer.com

2016年9月1日星期四

Mid-wavelength type II InAs/GaSb superlattice infrared focal plane arrays

Highlights:

•The superlattice materials were grown with both GaAs-like and InSb-like interface to balance the strain.

•The pixel was isolated by chlorine-based plasma etching together with citric acid-based chemical wet etching.

•The first device with 50% cutoff wavelength of 4.1μm shows NETD ~18mK from 77K based chemical wet etching.

•The NETD of the second device with 50% cutoff wavelength at 5.6 μm is 10 mK at 77K.

We have demonstrated 384×288 pixels mid-wavelength infrared focal plane arrays (FPA) using type II InAs/GaSb superlattice (T2SL) photodetectors. Two p-i-n T2SL samples were grown by molecular beam epitaxy with both GaAs-like and InSb-like interface. The diode chips were realized by pixel isolation with both dry etching and wet etching method, and passivation with SiNx layer. The device one with 50% cutoff wavelength at 5.6 μm is 10 mK at 77K. Finally, the T2SL FPA shows high quality imaging capability at the temperature ranging from 80K to 100K which demonstrates the devices’good temperature performance.

Keywords

  • Type II InAs/GaSb superlattice;
  • Focal plane arrays;
  • Mid-wavelength infrared
Source: Sciencedirect

If you are more interesting in GaSb wafer,please send emails to us: sales@powerwaywafer.com and visit our website: www.powerwaywafer.com

Transparent and electrically conductive GaSb/Si direct wafer bonding at low temperatures by argon-beam surface activation

Highlights

Direct, argon-beam activated n-GaSb/n-Si wafer bonding established.
GaSb deoxidation without altering the surface topography.
Fully bonded wafer pairs with high bonding strengths.
Optical transparency of the boundary layers.
Low interface resistivities <5 mΩ cm2 by optimization of the process parameters.

Direct wafer bonds of the material system n-GaSb/n-Si have been achieved by means of a low-temperature direct wafer bonding process, enabling an optical transparency of the bonds along with a high electrical conductivity of the boundary layer. In the used technique, the surfaces are activated by sputter-etching with an argon fast-atom-beam (FAB) and bonded in ultra-high vacuum. The bonds were annealed at temperatures between 300 and 400 °C, followed by an optical, mechanical and electrical characterization of the interface. Additionally, the influence of the sputtering on the surface topography of the GaSb was explicitly investigated. Fully bonded wafer pairs with high bonding strengths were found, as no blade could be inserted into the bonds without destroying the samples. The interfacial resistivities of the bonded wafers were significantly reduced by optimizing the process parameters, by which Ohmic interfacial resistivities of less than 5 mΩ cm2 were reached reproducibly. These promising results make the monolithic integration of GaSb on Si attractive for various applications.

Keywords:
  • Direct wafer bonding;
  • Argon-beam surface activation;
  • Gallium antimonide;
  • Heterojunction;
  • Carrier transport
  • GaSb
Source: Sciencedirect

If you are more interesting in GaAs wafer,please send emails to us: sales@powerwaywafer.com and visit our website: www.powerwaywafer.com