The Study of Interface Electrical Behavior of Contact between Electroless Plating and Electroceramics

Abstract

本研究乃應用複阻抗方法分離出半導電鈦酸鍶鋁陶瓷的界面電阻(晶界電阻與電極陶瓷接點電阻的和)與晶粒電阻。在居里溫度時，界面電阻聚增，但晶粒電阻則否。在樣品受到數次的加熱與冷卻循還過程之後，含低液相助燒結劑 AST(Al2O3-SiO2-TiO2)，且具大晶粒之樣品呈現遲滯(hysteresis)。此乃歸因於在居里溫度相變點時，由於大晶粒中發生強大的彈性應變，阻止晶體發生相變所造成的遲滯現象。在熱循環之初，樣品之界面電阻改變較大，但在數個循環之後，界面電阻則趨於穩定。就對熱循環的阻抗來說，電極材料鋁膠最穩定，銀膠則最差。其中鋁膠與無電鍍鎳與半導電鈦酸鍶鋇電子陶瓷之間的接觸電阻屬歐姆性，而銀膠與無電鍍銅的電極陶瓷間接觸電阻分別約為1000歐姆與550歐姆。

Complex impedance technique is successfully applied to separate thegrain resistance from the interface resistance, which is the summation ofgrain boundary resistance and electrode-ceramics contact resistance, of thesemiconducting (Sr0.2Ba0.8)TiO3:Sb3 ceramics. The fromer does not vary appreciably with temperature, while the latter increases abruptly at Curietemperature. The contact resistance (rc) of Al-paste and electroless Ni isapproximately ohmic and that of Ag- paste and electroless Cu is estimatedto be rc=lOOO Ω and 550 Ω, respectively. Hysteresis between heating and cooling cycles is observed for the interface resistance- temperature characteristics of large granular structure samples, which contain smaller amount of Al2O3-SiO2TiO2(AST) sintering aids.Thermal cycling is observed to modify the interfacial resistance significantly at the beginning, but it will reach a stable value after only a few cycles. Al-paste is the most stable electrode material when the resistance to thermal cycling is of concern, while the Ag-paste is the worst one.