Focused ion beam implantation for opto- and microelectronic devices

Abstract

Focused ion beam implantation is a powerful technology for the fabrication of opto- and microelectronic devices. Optoelectronic devices like gain coupled distributed feedback lasers and nonabsorbing waveguides can be defined in semiconductor heterostructures by the band gap shift due to highly spatially resolved implantation induced thermal intermixing. Single mode emitting devices were fabricated with emission wavelengths of 1 and 1.55 μm in the material systems GaInAs/(Al)GaAs and GaInAsP/InP, respectively. Band gap shifts of more than 65 meV could be reached in GaInAsP quantum film structures which simplifies the integration of nonabsorbing waveguide sections with, e.g., lasers, modulators, and detectors. In highly doped semiconductor layers semi-insulating areas could be defined by focused ion implantation. Depletion lengths down to 50 nm can be controlled and were demonstrated on current injection restricted resonant tunneling devices. By using this technique collector-up heterobipolar transistors were fabricated which exhibit current amplification factors up to 45.

Direct-Write Ion Beam Lithography

“…Besides dopant implantation, another technique for semiconductor processing is FIB implantation induced intermixing (upon thermal annealing) of superlattices. Impurity induced layer disordering allows for altering effective band gap and refractive index in desired regions of quantum well heterostructures, which finds immediate application in optoelectronic devices [92][93][94][95][96]. Both dopant implantation and intermixing techniques work with low ion doses and therefore with very reasonable IBL processing times.…”

Microfabrication techniques using focused ion beams and emergent applications

“…FIB have been used in numerous applications in experimental electronic and electro-optic device fabrication (Kalburge et al, 1997;Konig et al, 1998). Significant research efforts have been made to achieve ion implantation (Musil et al, 1996;Crell et al, 1997), device patterning (Gamo, 1991;Nagamchi et al, 1996) and FIB stimulated deposition of conductors and opaque films (Vasile and Harriott, 1989;Gross et al, 1990) …”