Application of selective area zinc in-diffusion for localized p-n junctions in integrated electro-optic devices

Monolithic integration is crucial for the development of optoelectronic integrated circuits that offer higher functionality than discrete devices. One of the main requirements in the implementation of any integrated circuit is the ability to address different parts of chip either electrically or optically. For electro-optic devices, these different areas need to be electrically isolated from one another. One approach that is routinely used in the semiconductor industry is the proton implantation, which very effectively produces high resistivity material for the electrical isolation. However, the process also leads to defects that are harmful to the performance of active optoelectronic devices. In this work, we report the use of selective zinc indiffusion in n-type semiconductors as a viable method of creating isolated islands of p-n junctions. We used this process to fabricate a symmetric integrated Mach-Zehnder modulator in which only one arm is subjected to an applied electric field for electro-optic modulation. In our initial device a 10dB contrast ratio was attained with about 5V reverse bias