Demonstration of Ultra-Fast Switching in Nanometallic Resistive Switching Memory Devices

Interdependency of switching voltage and time creates a dilemma/obstacle for most resistive switching memories, which indicates low switching voltage and ultra-fast switching time cannot be simultaneously achieved. In this paper, an ultra-fast (sub-100 ns) yet low switching voltage resistive switching memory device (“nanometallic ReRAM”) was demonstrated. Experimental switching voltage is found independent of pulse width (intrinsic device property) when the pulse is long but shows abrupt time dependence (“cliff”) as pulse width approaches characteristic RC time of memory device (extrinsic device property). Both experiment and simulation show that the onset of cliff behavior is dependent on physical device size and parasitic resistance, which is expected to diminish as technology nodes shrink down. We believe this study provides solid evidence that nanometallic resistive switching memory can be reliably operated at low voltage and ultra-fast regime, thus beneficial to future memory technology.

An Alignment Method for Lift-Off on Shallow Grooves in Transparent Substrates for Integrated Dual Grating Structures

In this Paper, we Propose an Alignment Method for Lift-Off on Shallow Grooves in Transparent Substrates without an Extra Mask. An Assistant Metal Layer Was Deposited on the Glass Substrate with Grooves to Increase the Reflectance, and then a Layer of Photoresist for Lift-Off Process Was Coated and Patterned Aligning with the Shallow Grooves. We Compared the Effect of Aluminum and Chromium Films with Different Thickness as Reflecting Layers. an Aluminum or Chromium Film with the Thickness Larger than 10nm Provides High Enough Image Contrast of Profile of the Alignment Marks Beneath the Photoresist. the Image Contrast of Contour Profile of the Marks Was Enhanced as the Thickness Increased. Lift-Off Process Was then Implemented on the Assistant Reflecting Layer. With a 20nm Cr Layer, we Successfully Did Lithography and Finished the Lift-Off Process to Pattern a Cr/Au Layer on Shallow Grooves in a Glass Wafer. Finally, the Assistant Cr Layer Was Removed Using Dry Etching. the Assistant Metal Layer Has No Undesirable Influence on the Following Process and the Device Property.