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ECE Colloquium Series – Jin-Woo Han, Ph.D.
October 5, 2017 @ 3:30 pm - 5:00 pm
As part of the *Eleanore Hale Wilson Lecture Series, ECE is proud to present:
Sustainable Semiconductor for Personal Satellite and Deep Space Exploration
Jin-Woo Han, Ph.D.
NASA Ames Research Center
Host: Professor Jeong-Hyun Cho
As silicon devices scaling advances, a long-term operation becomes increasingly less sustainable due to several device aging mechanisms. A failure rate of the device tends to increase with miniaturization and new space applications by various wear out mechanisms including stress induced leakage current (SILC), hot-carrier injection (HCI), and bias temperature instability (BTI). In addition to those reliability concerns, total ionizing dose (TID) degradation caused by ionizing radiation appears as important measure in ultra light weight vehicle along with long term (>20 years) space exploration such as wafer scale satellite, nano-spacecraft and satellite-on-chip. These wear out mechanisms collectively limits the stability and lifetime of circuit. In this seminar, two independent strategies are discussed to overcome reliability issues.
First, if the device degradation can be recovered in a controllable manner akin to the human immune system, the reliability and lifetime for personal satellites and deep space vehicles can be improved. Regardless of the type of degradation mechanisms, the results of SILC, HCI, BTI, and TID appear as bulk trapped charge and interface states in the gate dielectrics and the field oxide. The recoveries of SILC, HCI, BTI, and TID through thermal annealing are respectively demonstrated from many literatures. It has long been known that the process induced defects including missing atoms in the lattice, charge traps, and dangling bonds are recovered by thermal treatment. In this respect, the space semiconductor immunity system that is capable of detecting and recovering to any number of possible assaults is attractive in order to keep the chip working optimally on-the-fly. A heating element in different forms are embedded in different silicon circuits and the on-demand recovery is introduced. Also, the self-healing systems that is applicable for generic devices is demonstrated.
Second, a nanometer scale vacuum channel transistor is provided, which combines the advantages of both vacuum and solid-state electronics. The vacuum channel transistor can be fabricated and integrated with semiconductor process technology, providing compactness as well as high performance. To degrade the device, the radiation needs to traverse some distance in the channel to release its energy and liberate electrons from silicon atom. Therefore, the only approach to completely avoid the radiation effects is utilizing nothingness. With this regard, a vacuum is considered as the channel of transistor. The fabricated vacuum channel transistor is introduced and the radiation immunities are experimentally assessed.
Dr. Jin-Woo Han is currently a Research Scientist at the Center for Nanotechnology, NASA Ames Research Center (Moffett Field, CA), where he leads a team on nano-enabled device development, with a focus on beyond-CMOS devices, nanoscale electronics, and sensors. His work on wearable crossbar memory, self-healing electronics, and vacuum nanoelectronics, in particular, has received significant attention. He is currently serving as a technical committee in IEEE Electron Device Society and IEEE International Electron Device Meeting (IEDM). He received Presidential Early Career Awards for Scientists and Engineers from President Obama, IEEE Nanotechnology Council Early Career Award in 2016, IEEE EDS Early Career Award in 2012. He received the Ph.D. degree with highest honor from KAIST, Korea, in 2010.
*Established in 2009, the Eleanore Hale Wilson Fund supports engineering field leaders for travel to Minnesota to share their expertise and discoveries with University of Minnesota graduate students, faculty, and alumni. The fund also supports the receptions held in honor of each speaker.