Process Yield and Device Stability Improvement for Sol-gel Alumina Passivation layer based GFETs
The stability of GFET devices is a major problem and needs a good passivation layer for the same. Low cost and low-temperature sol-gel alumina passivation layer-based GFETs is studied here with the goals to improve stability of the device and achieve high process yield. The process yield and device stability are explored for two different molarities of 0.1 M and 0.05 M. The parameters like mobility, trap charge density, minimum conductivity plateau width and minimum conductivity are extracted to compare the stability of devices. The results indicate that GFETs with 0.1 M have problems of process yield due to crack formation in the channel region post-annealing, where close to half of the devices are working, and also working devices are are not stable and degrading very fast within a week's time. On the other hand, 0.05 M sol-gel Alumina-based sample exhibits 100$\%$ process yield with all working devices and observed stable behavior for more than two months. Hence we propose an optimized process recipe for a sol-gel Alumina-based passivation layer to achieve the best possible process yield and device stability for GFETs.