The transfer of continuous-relief micro-optical structures from resist into GaAs by the use of direct-write electron-beam (<i>e</i>-beam) lithography followed by dry etching in an inductively coupled plasma is demonstrated. BCl<sub>3</sub>-Ar chemistry was found to give satisfactory results; N<sub>2</sub> and Cl<sub>2</sub> were added to change the selectivity between GaAs and <i>e</i>-beam resist. The transfer process generates smooth etched structures. Distortion of the diffractive structures in the transfer process was examined. Blazed gratings with a period of 10 μm were optically evaluated with a 940-nm VCSEL. This grating was a five-step approximation of a blazed profile. The diffraction efficiency was 67% in the first order, with a theoretical value of 87%. Also, simulations of the optical performance of the transferred diffractive elements were made by use of a Fourier transform of the grating profile. Our goal is to integrate micro-optical structures with VCSELs.
© 2002 Optical Society of America
(050.1970) Diffraction and gratings : Diffractive optics
(140.3300) Lasers and laser optics : Laser beam shaping
(160.6000) Materials : Semiconductor materials
(220.4000) Optical design and fabrication : Microstructure fabrication
(350.3950) Other areas of optics : Micro-optics
Mikael Karlsson and Fredrik Nikolajeff, "Transfer of Micro-Optical Structures into GaAs by Use of Inductively Coupled Plasma Dry Etching," Appl. Opt. 41, 902-908 (2002)