Watson, George Patrick
Email Address
ORCID
Disciplines
Search Results
Now showing 1 - 4 of 4
Publication Influence of NaOH Concentration on Transfer Process of Graphene(2019-09-13) Saldana, Francisco; Wen, Chengyu; Watson, George PatrickThe process of transferring a monolayer of graphene using two different concentrations of sodium hydroxide (NaOH) solution unto a silicon dioxide (SiO2) coated Si chip using electrochemistry was performed. The transfer process is crucial for the delamination of a continuous graphene monolayer film from copper foil. After examining and inspecting the integrity of the graphene monolayer, it was observed that the lower concentration to NaOH led to slower rate of hydrogen bubble generation; this condition was found to be less destructive and yielded a graphene film with fewer visible tears.Publication Optimization of Bilayer Lift-Off Process to Enable the Gap Size of 1μm Using LOR 3A and S1813(2021-01-29) Suh, Yeonjoon; Watson, George PatrickBilayer lift-off process for 1μm feature size is demonstrated using LOR 3A and S1813 photoresist. The thickness of photoresists was fixed, whereas development time is varied. The process was further investigated by measuring the undercut depth and undercut rate by scanning electron microscopy. An optimized and reproducible recipe is provided.Publication Effect of Annealing on the Contact Resistance of Aluminum on a p-type Substrate(2019-11-14) Shah, Shrey; Watson, George PatrickAluminum contacts are widely used to form both ohmic and rectifying contacts. The process to form these contacts involves annealing, thus it is important to study the effect of annealing on the electrical properties of the contacts. Here, we present a way to measure the contact resistance of aluminum contacts formed on a p-type silicon substrate. It was found the contact resistivity decreased by an average of 18%. It was thus found that annealing at 400°C in a forming gas environment improves the electrical properties of aluminum contacts.Publication Correction of pattern size deviations in the fabrication of photomasks made with a laser direct-writer(2019-10-04) Xie, Ningzhi; Watson, George PatrickWhen using Heidelberg DWL66+ laser writer to fabricate the photomask, the pattern feature dimensions may have deviations. These deviations can be caused by the lithography process and the undercut in the metal etch process. The same deviation value of 0.8µm was found to appear in all the patterns independent of the pattern original size and local pattern density. To overcome this universal deviation, a universal bias is suggested to be applied to the original patterns during the data preparation for the lithography process. In order to ensure this pre-exposure bias method can work, both the laser direct-write exposure conditions (laser power, filters, focus parameters) and the metal etch time should be kept consistent.