Browsing by Author "Huang, Kuan-Chang"

Now showing 1 - 3 of 3

Experimental and Numerical Investigations on Jet Impingement Cooling for Electronic Modules
(2019-10-01)
Chu, Wen-Xiao
;
Huang, Kuan-Chang
;
Amer, Mohammed
;
Wang, Chi-Chuan
;
機械工程學系
In this paper, the influence of outlet arrangement and plenum structure on impingement cooling is experimentally and numerically investigated in a typical 1-U confined server space. Three outlets include Z-type, bilateral, and U-type arrangements, and the plenum configurations contain partially inclined, fully inclined, and staged layouts. As a result, using the U-type outlet or staged plenum may prominently compromise the impingement cooling performance on the target plates with lower pumping power. With numerical investigation, it is found that, for the case with Z-type outlet, the flowrate of jet impingement increases alongside the streamwise direction. Besides, the impingement stagnation region on target plates with the minimum thermal resistance may shift toward the outlet. Meanwhile, the uniformity of jet impingement can be improved by 10.7% and 50.3% when the bilateral and U-type outlets are applied, respectively, and the jet impingement is changed to perpendicular direction due to the opposite cross flow from the coming flow direction. On the other hand, by applying the inclined plenum and staged plenum, the uniformity of jet impingement can be dramatically improved by 113.9% and 215.1%, respectively. However, the local jet impingement velocity distribution is still nonuniform. Hence, a novel design of impingement plate based on the concept of Coanda effect is proposed. The peak value of the thermal resistance on target plate can be reduced by 21.8% and 16.0% at the center region and the fore part of the jet array.
Investigation of thermal stability and reliability of HfO2 based resistive random access memory devices with cross-bar structure
(2015-05-14)
Chand, Umesh
;
Huang, Kuan-Chang
;
Huang, Chun-Yang
;
Ho, Chia-Hua
;
Lin, Chen-Hsi
The effect of the annealing treatment of a HfO2 resistive switching layer and the memory performance of a HfO2-based resistive random access memory (cross-bar structure) device were investigated. Oxygen is released from HfO2 resistive switching layers during vacuum annealing, leading to unstable resistive switching properties. This oxygen release problem can be suppressed by inserting an Al2O3 thin film, which has a lower Gibbs free energy, between the HfO2 layer and top electrode to form a Ti/Al2O3/HfO2/TiN structure. This device structure exhibited good reliability after high temperature vacuum annealing and post metal annealing (PMA) treatments. Moreover, the endurance and retention properties of the device were also improved after the PMA treatment. (c) 2015 AIP Publishing LLC.
Mechanism of Nonlinear Switching in HfO2-Based Crossbar RRAM With Inserting Large Bandgap Tunneling Barrier Layer
(2015-11-01)
Chand, Umesh
;
Huang, Kuan-Chang
;
Huang, Chun-Yang
;
Tseng, Tseung-Yuen
;
電子工程學系及電子研究所
In this paper, the nonlinear switching mechanism of the Ti/HfO2/Al2O3/TiN crossbar structure resistive random access memory device with good reliability is investigated. The nonlinearity of the device can be revealed by inserting a large bandgap of an Al2O3 thin layer between the TiN bottom electrode and the HfO2 switching film. The nonlinear switching mechanism caused by Flower-Nordheim tunneling involves the tunneling barrier of the Al2O3 layer. Besides, the nonlinear behavior is also sensitive to the thickness of the inserting Al2O3 layer. A high nonlinear factor of 37, large endurance more than 10(4), and good retention properties are achieved in the Ti/HfO2/Al2O3 (1-nm)/TiN structure.