無電鍍鈀誘發非晶矽薄膜結晶的研究

Abstract

在本論文中，提出金屬誘發結晶(MIC)/金屬誘發側向結晶(MILC)的製程，即利用無電鍍的方式鍍覆鈀(Pd)在非晶矽(a-Si)薄膜的表面當晶核來誘發結晶。無電鍍方式鍍覆的鈀(Pd)會均勻的分佈在非晶矽(a-Si)膜表面。而且在550℃下退火1小時，即可得到針狀的結晶。 另外，針對已有蝕刻圖案(pre-pattern)的非晶矽(a-Si)薄膜，利用無電鍍方式鍍覆的鈀(Pd)會選擇性沈積在島狀非晶矽的側邊(sidewall)處。在經過退火後，可觀察到長針狀的複晶矽(poly-Si)結晶，而且大部分的結晶具相同的方向且與島狀非晶矽的側邊夾約55。角。根據這個發現，我們提出一個新的薄膜電晶體結構。 新的結構的薄膜電晶體的電性比傳統的薄膜電晶體好，這是因為針狀晶粒的方向和載子移動方向平行。在經過NH3電漿處理過以後，元件特性獲得明顯的改善。

In this thesis, metal-induced crystallization (MIC) / metal-induced lateral crystallization (MILC) processes using metal seed layer by electroless Pd plating method was proposed. The Pd clusters formed by electroless plating method uniformly distributed on the surface of amorphous silicon (a-Si) films. Needle-liked polycrystalline silicon (poly-Si) films were obtained when the a-Si films with electroless plating Pd were annealed at 550 ℃ for 1 hr. For the pre-patterned a-Si films, Pd clusters were preferred to deposit on the sidewalls of the silicon island. After the samples were annealed, long needle-liked poly-Si grains were observed. Most of the grains were lying in the same direction with an angle of ~55° from the sidewalls of the silicon island. Based on this finding, a new TFT structure was proposed. The electron characteristics of the new TFT structure are better than that of the conventional TFT structure. This attributes that the orientation of needle-liked grain parallel the moving direction of carrier. The characteristics of TFT are improved by NH3 plasma treatment.