5-1 結論
本論文將真空管的工作原理應用在半導體固態元件中，設計了空間電荷限制電晶 體，工作原理就像固態的真空管一般，以柵極的電壓控制載子從射極至集極所遭遇之能 障。製作方法係在透明導電玻璃基板上完成，具有與有機發光元件整合之可能性。在初 代結構設計的空間電荷限制電晶體之集極電流的確是可以被柵極電壓所調控的，開關比 可達到(On/Off ratio)428，電流密度約 27mA/cm2。
在嘗試對初代結構空間電荷限制電晶體做結構上改良之後，即產生了新穎式空間電 荷限制電晶體。新穎式結構以絕緣體來取代初代結構的第一層半導體，如此可大幅減低 Off current，且因只須沉積一次半導體層而簡化製程步驟。新穎式空間電荷限制電晶體 不僅可以作用無誤，甚至降低操作電壓至2V 以及提高開關比(On/Off ratio)達到 10775，
電流密度約5.15 mA/cm2 。
本論文最後證明了沉積半導體與氧電漿處理之時距與電晶體在低電壓之行為高度 相關，並優化了新穎式結構空間電荷限制電晶體在低電壓之元件特性，電晶體降低操作 電壓至0.8V 以內並維持高開關比(On/Off ratio)約為 104，電流密度約1.36 mA/cm2，電流 增益（集極電流／柵極電流）約為104。
總結本論文，空間電荷限制電晶體從初代結構至新穎式結構乃至低電壓改良後之特 性皆有顯著改善(表 5-1)，尤其開關比(On/Off ratio)與操作電壓(Operation Voltage)皆大幅 提升。電流密度(Current density)之降低乃因操作電壓降低，而非元件載子遷移率下降所 致。
空間電荷限制電晶體已經大幅提升開關比與電流增益至104，再提升的空間有限。
On current 主要取決於半導體材料之載子遷移率;而 Off current 則取決於孔洞分佈與絕緣 體之絕緣性質，故要再大幅提升開關比，唯有走上更換絕緣體或半導體材料之途。
On/off ratio Current gain
Operation voltage
Output current density 初代結構之SCLT
428 10
36V 27 mA/cm
2 新穎式結構SCLT10
410
4<2V 5.15 mA/cm
2 低電壓改良後之新穎式結構SCLT
10
410
4<0.8V 1.36 mA/cm
2表5-1，三次改良之空間電荷限制電晶體元件特性改善。
5-2 未來展望
空間電荷限制電晶體的許多操作特性已滿足軟性電子產業需求，未來應朝大面積主 動式陣列製程發展，以期整合其他元件做主動式陣列掃描，例如:有機發光二極體、各式 感測器等。
相對於水平結構的FET來說，空間電荷限制電晶體的垂直結構元件屬於高速元件，
這是FET所無法取代的，此結構也擁有許多製程上的優點，不需要複雜且昂貴的微影設 備，在有機高分子電晶體領域中，縱使大多數科學家仍是以研究FET為主流，但隨著時 間過去，越來越多不同結構的有機高分子電晶體文獻被發表，垂直結構也開始有越來越 多的科學家投入，這是科學家及研究人員們所樂見的，相信在有機高分子半導體成熟之 後，人類的生活會進入另一個新紀元。
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