a team of researchers from the agency for science, technology, and research (a*star) in singapore has developed a new method for manufacturing a hybrid iii-v semiconductor and silicon-on-insulator (soi) optical microcavity that will reduce the complexity of fabricating hybrid silicon lasers, according to a report on the agency’s website.

a*star researchers have developed a new manufacturing method for silicon lasers.
(wikimedia commons)

“hybrid silicon lasers combine the light-emitting properties of group iii–v semiconductors, like gallium arsenide and indium phosphide, with the maturity of silicon manufacturing techniques,” the report explained. “these lasers are attracting considerable attention as they promise inexpensive, mass-producible optical devices that can integrate with photonic and microelectronic elements on a single silicon chip.”

the current process is to produce lasers on separate iii-v semiconductor wafers that have to be aligned individually to each silicon device. this is both time-consuming and limits the number of lasers on a chip.

to overcome this challenge, the researchers attached “a thin film of iii–v semiconductor to a silicon oxide (sio₂) wafer using a soi interlayer thermal bonding process, they produced a strong bond that also removes the need for strong oxidizing agents, such as piranha solution or hydrofluoric acid.”

the dual hard-mask technique also limited the etching to the intended layer and eliminated the need for multiple overlay lithography and etching cycles.

“the work presents, for the first time, a new heterocore configuration and integrated fabrication process that combines low-temperature sio₂ interlayer bonding with dual hard-mask, single lithography patterning,” the researchers said.

the research was recently published in acs photonics. the abstract stated:

“heterogeneously integrated heterocore microcavity iii–v semiconductor lasers on silicon-on-insulator (soi) are fabricated and demonstrated in this paper. the heterocore microcavity is realized via ultrathin silicon dioxide interlayer bonding of iii–v on soi and dual hard mask technique.

“the dual hard mask technique utilizes flowable oxide and silicon nitride as etch masks for iii–v and soi etchings, respectively, and hence, a single lithography is required in the fabrication. compact optical-pumped heterocore microdisk lasers are demonstrated and their lasing performances are characterized.”