NH3及N2O對介電質的影響

Abstract

本論文主要是探討如何改善介電質的品質，所用來成長介電質的氣體主要 是O2和TEOS。根據處理方法的不同，可以分為下列四個部份：第一部份： 這部份主要是討論NH3和N2O對介電質的影響。首先用氧氣長一層介電質， 再用不同的氣體﹝NH3及N2O﹞處理，所得介電質再與純氧所長出來未處理 的介電質做比較，以瞭解NH3和N2O對介電質的影響。第二部份：這節主要 是探討用TEOS所長出來介電質的特性。我們先用TEOS長一層介電質，再用 不同的氣體﹝NH3，N2O及O2﹞處理，以瞭解用TEOS所長出來介電質的品質 。第三部份：眾所皆知，用純N2O所長出來的介電質有很好的品質，所以 這部份用N2O來長介電質，並和其他方法所長出來的介電質做比較，以驗 證此觀點。第四部份：這部份是探討介電質長在不同薄膜上的特性。首先 在多晶矽上長一層薄膜﹝分別為Si3N4及a-Si﹞然後再通入氧氣來產生介 電質，然後和純氧在多晶矽上所長出來的介電質品質做比較，看是否有所 改善。根據以上所得結果可知：用純N2O所長出來的介電質品質最好，但 由於所需費用高，以及長成時間久，所以我們可先用TEOS出介電質後再用 處理的方法也可以得到不錯的結果，並降低成本。 This thesis is focused on the exploration of improving the quality of interpoly dielectric. The gases which are used for growing dielectric are O2 and TEOS. According to the processes, we can divide it into four parts:Part I : This part discussed the effects of NH3 and N2O on interpoly dielectric. First, we used oxygen to grow dielectrics, and then annealed the sample in different gases NH3 and N2O, respectively. After the dielectrics were grown, we compared their qualities with the dielectric without any treatment to study the effects of NH3 and N2O on dielectrics.Part II : This section focused on exploring the characteristics of TEOS-deposited dielectric. First, we used TEOS to deposit the dielectrics, and then annealed the sample in different gases NH3, N2O, and O2, respectively. After the dielectrics were grown, we can investigate the characteristics of TEOS-deposited dielectrics.Part III : N2O-grown dielectric is well known to have a good quality. So, this part used N2O to grow the dielectric and compared the quality with the other dielectrics to support this point.Part IV : This part explored the characteristics of different films on which the dielectrics were grown. Before growing the dielectrics, we grew a thin film , i.e. nitridation of poly-1 and a-silicon, respectively, on polysilicon. Then we used oxygen to grow the dielectrics on these thin films. After these dielectrics were grown, we compared their qualities with the dielectric which was grown on the polysilicon to see if the qualities were improved.According to the results above, the N2O-grown dielectric indeed has the best quality. However the disadvantages are the high budget and long growing time. So, we can use TEOS-deposited dielectric annealed in N2O ambient to get a quite good quality of dielectric and to reduce the budget.