微機電螺旋電感整合鎳鐵-陽極氧化鋁奈米複合物之製成以及特性

Abstract

在這篇研究當中提出了一個具有懸浮狀微機電式結構的單晶片螺旋電桿整合鎳鐵(鎳占83%,鐵占17%)-陽極氧化鋁奈米複合物之製造過程以及其特性, 其中我們已經可以成功的在矽基板上將直徑60~70奈米的鎳鐵奈米柱經由電鍍的方式將其置入在陽極氧化鋁模板內, 對一個三圈半的電感而言,利用鎳鐵磁性柱來提升感值已達到約16%的增強並持續增強到1GHz,但卻伴隨著品質因子下降約55%以及電感自身的共振頻率移向低頻這兩個問題, 產生的原因在於用來當種晶層的鈦所產生的大寄生電容效應, 為了要降低這層鈦所帶來的效應以及提升品質因子, 一道利用氟化氙氣體的後製程在此被引入來等向性移除電桿下方的矽基板使的鈦層可以露出來, 接著再利用濕蝕刻的方式來把這層暴露出來的鈦移除掉, 從實驗結果來看, 利用這個方法可以成功的將品質因子增強到幾乎快跟不加磁性材料時的電感一樣好, 並且可以觀察到共振頻率有往後增加了將近8GHz。

This study presents the fabrication and characterization of spiral inductors which is a suspended MEMS structure with NiFe(83 at% Ni and 16 at% Fe)-AAO nanocomposite core. The NiFe nanorods with 60~70nm diameter are electorplated and isolated in AAO(Anodic Aluminum Oxide) template on a silicon substrate. For a spiral inductor with a NiFe-AAO nanocomposite core, about 14% inductance improvement can be observed up to 1 GHz for a 3.5 turn NiFe-AAO inductor, but also accompanied with ~55% Q factor reduction and the resonance frequency shifts toward a low frequency regime due to the prasitic capacitance caused by Ti seed-layer. In order to reduce the effect of Ti layer and improve the Q factor, a post-process using XeF2 is employed to remove the silicon substrate underneath the inductor isotropically and then to remove the Ti layer by wet etching process. The experimental results show that maximum Q factor can successfully be improved as good as the one with the air-core spiral inductors, and about 8 GHz increasment in self-resonane frequency can also been observed.