针对40Gb/s高速过渡热沉阻抗匹配的要求,对基于Ta2N薄膜的匹配电阻制作工艺进行了系统研究.根据过渡热沉的等效电路模型,分析了Ta2N薄膜电阻与传输线电极间接触电阻对高频反射特性的影响,并通过理论仿真确定了热沉匹配电阻的容差范围.利用磁控反应溅射技术,制作出特性稳定、方阻可调的Ta2N电阻薄膜.通过优化高温退火条件,将电阻薄膜与金属电极间的比接触电阻率降至10^-6·Ωcm^2量级.在此基础上,制作出了性能良好稳定、可应用于40Gb/s光电子器件封装的高速过渡热沉.
A systematic study of the fabrication process of Ta2N thin-film resistor was presented to meet the impedance matching requirement of 40Gb/s high-speed submount. Equivalent circuit of the submount was proposed to analyze the influence of contact resistance on the reflection characteristics at high frequencies. And the resistance tolerance of the thinfilm resistor was determined based on the numerical simulation. Ta2N thin-film with a stable and adjustable sheet resistance was fabricated by reactive sputtering. Specific contact resistivity between the Ta2N thin-film and metal electrode was reduced to 10-6 Ω· cm^2 by optimizing the annealing temperature. Based on these results, high-speed submount with stable and high transmission performance was fabricated for the packaging of 40Gb/s optoelectronic devices.