(1)於電阻性記憶體的量測上,ND-ZnO 層的沉積時間在 0 分鐘和 2.5 分鐘的樣品 僅具備一次性的功能而無法復元。當ND-ZnO 層的沉積時間在 5 分鐘和 10 分 鐘時可以達成狀態切換的功能。而當ND-ZnO 層沉積時間為 15 分鐘時則 元件的 通道較少使得切換變困難。
(2)當 IS 狀態量測時,由文獻[42]的結果得知在 ND-ZnO 層和二氧化矽接面上會產 生內建電場,此時電子電洞要復合時也較沒有ND-ZnO 層的樣品容易。所以 才會有位障變高但在SET 狀態時 ρint最低在樣品HP_N2.5_I 的情形出現。
(3)從 300℃至 700℃熱處理的樣品皆無法從 SET 轉換至 RESET,而且 700℃和 900 ℃熱處理的ND-ZnO 層樣品有溫度過高導致晶粒再結晶的疑慮。
(4)於 IS 狀態的量測中,我們將 I-V 曲線的量測分成兩個區域。第 I 區的指 數值大致維持穩定。第II 區的 α 在樣品 HP_N2.5_I 和 HPN_a300_I 沒有太大 變化所以屬於穿隧的機制。而其他樣品在第II 區則因為溫度而有不同斜率 的變化狀況,其原因可能是ND-ZnO 層之中有很多缺陷,經過我們多次的 量測以及升溫的影響促使缺陷漸漸形成通道而造成元件串聯電阻變小。所以 可 能影響到我們量測的α 值。
(5)在 SET 狀態時,不同高度 ND-ZnO 層樣品的接面電阻 ρint不會隨著溫度而改變,
所以其載子傳輸機制是屬於熱游子場發射(Thermionic field emission),此系列 樣品的接面電阻最低是在ND-ZnO 層成長 2.5min 時,大約可以維持在 4.5×10-3 Ω-cm2。
(6)經過不同熱處理溫度的一系列樣品中,呈現 SET 狀態的元件會因為溫度的升 高接面電阻會變小。所以其載子傳輸機制是屬於熱游子發射(Thermionic emission)。此系列 樣品的接面電阻最低是樣品 HPN_a500_I,大約是 6.6×10-3
至4.8×10-3(Ω-cm2)。
未來工作可能有以下幾項提升空間:
(1)提升電阻性記憶體的通道數量、ISET/IRESET的比值與穩定性。
(2)進一步降低元件於 SET 狀態時的接面電阻。
所以可能的具體作法是:
沉積ND-ZnO 層前先將基板做表面處理使 ND-ZnO 成長方向具一致性(如晶 種層、表面粗化),此做法預期可以提升元件的通道密度和狀態維持時的穩定性。
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