VCSEL Fabrication Processing The following is pictorial description

VCSEL Fabrication Processing The following is pictorial description of the fabrication process for oxidized VCSELs. A detailed description of each step is contained in “VCSEL Fab Details. ppt” This work was performed in Micro and Nanotechnology Laboratory at the University of Illinois by members of the Photonic Device Research Group

VCSEL fabrication – Bare wafer Cleave Label substrate backside Clean Photonic Device Research Group

VCSEL fabrication – Backside contact Target: 40 nm Au. Ge / 20 nm Ni / 150 nm Au Photonic Device Research Group

VCSEL fabrication – Spin PR Degrease /N 2 dry /Dehydration bake HMDS (can spin-on or vapor prime) Spin on photoresist (usually 4330) Photonic Device Research Group

VCSEL fabrication – Top contact lithography 4330 lithography Photonic Device Research Group

VCSEL fabrication – Metal deposition O 2 Plasma (300 W – 3 min) 1: 10 NH 4 OH: DI dip (15 sec) Flowing DI rinse (10 min) N 2 dry, inspect, load, evaporate Target: 15 nm Ti / 150 nm Au Photonic Device Research Group Photonic Group

VCSEL fabrication – Liftoff Acetone soak ~5 min / Squirt gun Photonic Device Research Group

VCSEL fabrication – Si. O 2 deposition Degrease, N 2 dry load, deposit dielectric > 400 nm thickness (based on color) Photonic Device Research Group

VCSEL fabrication – Si. O 2 pattern Degrease /N 2 dry /Dehydration bake HMDS vapor prime Spin on AZ 5214 Hardbake (110° C for 60 sec) Patern & develop Photonic Device Research Group

VCSEL fabrication – CF 4 RIE etch Freon 14 (CF 4) for > 400 nm (22 min) Remove PR mask with acetone Photonic Device Research Group

VCSEL – Si. Cl 4 ICP-RIE mesa etch Clean ICP (O 2 process – 15 min) ICP predep (Si. Cl 4 recipe – 10 min) Etch > 5 mirror pair into bottom DBR To be replaced by Semigroup RIE Photonic Device Research Group

VCSEL fabrication – Selective oxidation Oxidation rate from test piece Use optical (below) or electrical probe Record actual pinch off in log book Photonic Device Research Group

VCSEL fabrication – CF 4 RIE etch Freon 14 (CF 4) process (~200 Å/min) Test for conduction on probe station 2 min etch, test Repeat until all Si. O 2 is removed Photonic Device Research Group

VCSEL Structure and Operation Top-view optical photograph of fabricated VCSEL Side-view schematic of fabricated VCSEL Photonic Device Research Group

Test VCSELs! Photonic Device Research Group