Fabrication of electronic devices with an internal window

Abstract

A process is described of producing devices, such as vertical cavity surface emitting lasers or resonant cavity light emitting devices, with an insulating region between an active region and top electrode, the insulating region having a centrally located window permitting passage of the electric current from the top electrode to the bottom electrode centrally of the active region. The insulating region is formed by ion implantation. The window is defined by a photoresist mask formed by angle etching a photoresist masking layer by RIE, so as to form the mask with parallel side walls inclined at an angle to the normal to the masked surface. The ion implantation is conducted at the same angle and parallel to the side walls of the of the mask. This permits fabrication of devices individually or in arrays. An exemplary independently addressable top emitting 8.times.18 VCSEL array (VCSELA) with GaAs multi-quantum well gain region was fabricated with excellent properties using the angle etched masks. The typical threshold current and voltage of the exemplary devices in this array are approximately 4 mA and 2.65 V respectively. The L-I-V characteristics of the devices do not change by current annealing. Also, a comparison between devices produced by using the novel angled implantation mask and devices produced by using conventional lithography implantation mask indicates the importance of the implantation mask preparation on the final VCSEL operating characteristics.