Fabrication of GaSb microlenses by photo and e-beam lithography and dry etching

Ewa Papis 1Anna Piotrowska 1Eliana Kaminska 1Tadeusz T. Piotrowski 1Krystyna Golaszewska 1Jacek Ratajczak 1Jerzy Katcki 1Jerzy Wrobel 2

1. Institute of Electron Technology (ITE), al. Lotników 32/46, Warszawa 02-668, Poland
2. Polish Academy of Sciences, Institute of Physics, al. Lotników 32/46, Warszawa 02-668, Poland


GaSb and related semiconductors are well recognised for their potential application in mid-infrared optoelectronics and thermophotovoltaics. We have recently demonstrated fabrication of DH InGaAsSb/AlGaAsSb/GaSb mid-IR photodetectors with detectivity ranged from 5x1010 to 2x1011 cmHz1/2/W, depending on the active area and cutoff wavelength.
One of the possible way of improving photodetector performance is a monolithical integration of device structure with hemispherical/hyperhemispherical microlenses enabling effective concentration of IR radiation and increasing device detectivity.
In this work we present the results of fabrication lenses arrays in GaSb substrate using both resist reflow/dry etching and binary optics techniques. Photo and electron beam lithography techniques were used to define lenses pattern.
Surface morphology, diameters and shape of the lenses after dry etching were determined by optical microscopy with Nomarski contrast, SEM, and Tencor Alpha-step profilometer.
In the case of the resist reflow technique photoresist cylinders were melt into spherical lenses by heating on a hot plate at temperature over 200oC, depending on the lens diameter and thickness. In the pattern transfer process the control of the relative etch rates of the photoresist and substrate was critical to achieve the desired microlens properties. The sputter etching in Ar+ was chosen to etching refractive microlenses. Binary optics technology requires anisotropy etching with high selectivity between mask and substrate. Reactive ion etching in BCl3 plasma with RF power of 10W was used to transfer preshaped AZ PF514 electronoresist into GaSb substrate. We have obtained high quality spherical microlens arrays with diameters up to 10μm and circular gratings with 400nm linewidth and 1μm period.

This work is partly supported by the State Committee for Scientific Research under the grant No 4 T11B03922

Presentation typ

Related papers
  1. Application of Ti-Al-N MAX-phase for contacts to GaN
  2. Transparent p-type ZnO obtained by Ag doping
  3. Measurement of distorting magnetic field inside the scanning electron microscope with the use of microscope itself
  4. Determination of densities of various dislocation types in GaN – comparison of TEM and improved hot acid etching method
  5. Liquid phase growth and characterization of laterally overgrown GaSb epitaxial layers
  6. Photothermal investigations of SiC thermal properties
  7. Characterization of Ir and IrO2 Schottky contacts on n-type 4H-SiC under high temperature stress
  8. Determination of stress in composite engineered substrates for GaN-based RF power devices
  9. Passivation of GaN surface by chemical bath deposition of thin CdS layers
  10. Optimisation of electrochemical sulphur treatment of GaSb and related semiconductors: application to surface passivation of GaSb/In(Al)GaAsSb TPV cells
  11. Comparison of various GaSb-based device structures for application in thermophotovoltaic cells
  12. Optical properties of p-type ZnO:(N, As, Sb)
  13. Optical and magnetooptical properties of the p-type ZnMnO.
  14. TEM study of iridium silicide contact layers for Low Schottky Barrier MOSFETs
  15. Relationship between condition of deposition and properties of W-Ti-N thin films prepared by reactive magnetron sputtering
  16. Influence of enhanced temperature and pressure on structural transformations in pre-annealed Cz-Si
  17. Structural analysis of reactively sputtered W-Ti-N thin films
  18. Phase relationships in annealed Cu-Al-O layers
  19. TaSiN, TiSiN and TiWN diffusion barriers for metallization systems to GaN
  20. Transparent Conducting Oxides as Ohmic Contacts for GaSb-based Thermophotovoltaic Cells
  22. Thermally stable Ru-Si-O gate electrode for AlGaN/GaN HEMT
  23. Preparation and characterization of hexagonal MnTe and ZnO layers
  24. p-type conducting ZnO: fabrication and characterisation
  25. Diffusion barrier properties of reactively sputtered W-Ti-N thin films
  26. Study of Long-Term Stability of Ohmic Contacts to GaN
  27. Transmission Electron Microscopy of Iridium Silicide Contacts for Advanced MOSFET Structures with Schottky Source and Drain

Presentation: poster at E-MRS Fall Meeting 2003, Symposium F, by Ewa Papis
See On-line Journal of E-MRS Fall Meeting 2003

Submitted: 2003-05-26 16:39
Revised:   2009-06-08 12:55
Web science24.com
© 1998-2018 pielaszek research, all rights reserved Powered by the Conference Engine