玻璃相氧化鋅變阻器之缺陷研究

Abstract

利用深能階暫態系統研究鉛硼鋅矽玻璃相氧化鋅變阻器的缺陷.在實驗中, 量測到四個多數載子缺陷,定義為P1,P2,P3及High temp peak. P1,P2的活 化能分別為0.13eV及0.24eV,推論P1,P2為本質缺陷.由積層氧化鋅變阻器 的缺陷空間分佈研究,發現P2在晶界分佈較晶粒多,所以P2應該不是鋅間位 造成,比較可能為氧空缺或氧間位.P1受電場及結構影響較大,可能為鋅間 位,氧空缺,氧間位的聚集.P3具有寬廣的能階分佈,活化能約為0.4eV,應該 為interface state造成,P3的存在使變阻器較穩定,晶界層的結晶幫助P3 的形成,Mn會影響其能階分佈.High temp peak也具有寬廣的能階分佈,活 化能隨樣本位能障增加而增加,推測為兩晶粒間interface造成,能階分佈 機率在費米能階附近為最大. Deep level transsient spectroscopy measurements were per- formed to study the defects in ZnO-glass varistors. Four electron traps were observed: P1(Ec-0.13eV), P2(Ec-0.24eV), P3( Ec-0.4eV) and a high-temperature peak. P1 and P2 were re- lated to native defects. From the depth profile of P2, P2 shouldn't be associated with Zn interstitial. P2 should ori- ginate from Vo or Oi. P1 was associated with a cluster invo- lving Zn interstitial or Vo or Oi. P3 is a broad peak due to interface states. The existence of P3 was related to the st- ability of ZnO-glass varistors. Mn can affect the energy le- vels of P3. The crystallization of intergranular layers is helpful to the formation of P3. The high-temperature peak is also a broad peak, whose activation energy increased with en- ergy barrier height. The high-temperature peak is possibily due to the interface states at ZnO-ZnO grain boundaries.