Semiconductor Conductive Layers

Reference number: STC-PS-0670
Inventor(s): L. Dawson; P. Dowd; P. Hill; S. Krishna
For more information, contact: Erin M. Beaumont (505-272-7912) or Minh D. Tran (505-272-7937)

Patent(s)

7,583,715 (UNM-0670)

Background

Mid-wavelength infrared (MWIR) Optoelectronic devices have attracted a lot of attention recently. Lasers operating at wavelengths between approximately 2-6 µm are an essential component in optical systems which can be used for remote sensing, LADAR, detection of chemical warfare agents, intelligence, surveillance and reconnaissance (ISR), enemy missile tracking and infrared countermeasures (IRCM).

Edge-emitting lasers (EEL) require conductive layers on opposite sides of an active region, providing current flow through that active region. In conventional telecommunication and data-communication EELs, typical device structures perform adequately. However, for MWIR applications, it is generally difficult to form structures with both good optical and electrical performance.

In EELs, conductive layers are typically achieved by including highly doped layers. However, sufficiently high doping levels can be difficult to achieve for some semiconductor materials used in MWIR devices. Furthermore, in many compositions of the alloy, high electron concentrations can be difficult to obtain since the ionization energy can be relatively high.

Technology

This technology addresses novel techniques for the growth of conductive regions on opposite sides of an active region in devices, including EELs, for applications including MWIR devices and systems. This invention will form an improved conductive region by growing a digital alloy superlattice, where the thicknesses and compositions of the superlattice layers are chosen to provide the desired average composition of the bulk alloy, and at least one of the components of the superlattice has a low ionization energy such that high doping of that layer type can be achieved. Consequently, the conductivity of the superlattice conductive region is higher than that for a bulk alloy with the same average composition.

Applications/Advantages

This technology enables conductive layers with improved electrical properties, such as conductivity, to be achieved over other previously invented conductive layers used in such devices. This technology has applications for MWIR devices and systems that allow for structure formation with both good optical and electrical performance, as well as improved conductivity.

2.5–3.5 µm optically pumped GaInSb/AlGaInSb multiple quantum well lasers grown on AlInSb metamorphic buffer layers. E. A. Pease, L. R. Dawson, L. G. Vaughn, P. Rotella, and L. F. Lester, Journal of Applied Physics, 2003, vol. 93, issue 6, 3177.

Downloads

• UNM-670 Issued Patent (745.88 KB PDF)

Keywords

Semiconductors

Related Categories

• Lithography, Semiconductor Fabrications, and Electronic Materials
• Optoelectronics and Lasers