Vertically stackable novel one-time programmable nonvolatile memory devices based on dielectric breakdown mechanism

In this paper, a novel one-time programmable (OTP) nonvolatile memory (NVM) device and its array structures based on silicon technology are proposed. There have been many features of OTP NVM devices utilizing various combinations of channel, breakdown region, barrier, and contact materials. However, this invention can be realized by simple materials and fabrication methods: it is silicon-based materials and fully compatible with the conventional CMOS process. An individual memory cell is a silicon diode vertically integrated. Historically, OTP memories were widely used for read-only-memory (ROM) in the central processing unit (CPU) of the computer systems. By implanting the nanoscale fabrication technology into the concept of OTP memory, innovative high-density NVM appliances for massive storage media becomes very promising. The program operation is performed by breaking down the thin oxide layer between pn doped structure and wordline (WL) and its state can be sensed by the leakage current through the broken oxide. Since this invention is based on neither transistor structure nor charge-based mechanism, it is highly reliable and functional for the ultra-large scale integration. The feasibility of its stacked array will be also checked.