No abstract

Mechanism of improving forward and reverse blocking voltages inAlGaN/GaN HEMTs by using Schottky drain * Zhao Sheng-Lei(赵胜雷) a) , Mi Min-Han(宓珉瀚) a) , Hou Bin(侯 斌) b) , Luo Jun(罗 俊) a) , Wang Yi(王 毅) a) , Dai Yang(戴 杨) a) , Zhang Jin-Cheng(张进成) a) , Ma Xiao-Hua(马晓华) a)b) , and Hao Yue(郝 跃) a) † a)

A theoretical analysis of high-efficiency punch-through operation GaN-based terahertz IMPATT diodes has been carried out in this paper. It is shown that the negative differential mobility (NDM) characteristics of GaN coupled with the space charge effect acting as a self-feedback system can markedly increase the drift velocity of injection carriers, and thereby enhance diode performance under appropriate external RF voltage. The behavior of traveling electrons in the transit zone is investigated in detail. It is found that the IMPATT diode with a punch-through structure operating in the NDM mode exhibits superior characteristics compared with the equivalent diode operating in the Si-like constant mobility mode. In particular, the NDM-mode diode can tolerate a larger RF voltage swing than that operating in constant mobility mode. Numerical simulation results reveal that the highest efficiency of 26.6% and maximum RF power of 2.29 W can be achieved for the NDM-mode diode at a frequency of 225 GHz. A highest efficiency of 19.0% and maximum RF power of 1.58 W are obtained for the diode with constant mobility.

Q. (2012). Precipitation behavior of magnetite in oxide scale during cooling of microalloyed low carbon steel. Advanced Materials Research, 572 249-254.