A graphene nanoribbon (GNR) is an important basic structure to open a bandgap in graphene. The GNR processes reported in the literature are complex, time-consuming, and expensive; moreover, the device yield is relatively low. In this paper, a simple new process to fabricate a long and straight graphene nanoribbon with a high yield has been proposed. This process utilizes CVD graphene substrate and a ZnO nanowire as the hardmask for patterning. 8 mu m long and 50-100 nm wide GNRs were successfully demonstrated in high density without any trimming, and similar to 10% device yield was realized with a top-down patterning process. After passivating the surfaces of the GNRs using a low temperature atomic layer deposition (ALD) of Al2O3, high performance GNR MOSFETs with symmetric drain-current-gate-voltage (I-d-V-g) curves were demonstrated and a field effect mobility up to similar to 1200 cm(2) V-1 s(-1) was achieved at V-d = 10 mV.