論文摘要 本論文主要研究內容在於高截止頻率、高崩潰電壓之磷化銦雙異質接面雙極性電晶體的製程技術發展、以及元件結構的改善。 在製程方面，我們發展一套射極面積為1x10μm2的回蝕刻製程，此套製程可完全避免小尺寸元件開洞的問題，並且在製程裡，使用了基極金屬自我對準以及隔離台（isolation pad ）的技術，來有效的提高元件的高頻特性。 元件結構方面，我們在集極區使用了複合式集極結構，並且改變砷化銦鎵間隔層的厚度，來探討其間隔層厚度變化對於電流阻擋效應以及電子飽和速度的影響；最後我們利用回蝕刻製程並配合磊晶結構的改善，得到fT=255 GHz以及BVceo=6.24 V的元件特性，而在不使用深次微米的技術之下，這也是目前砷化銦鎵/磷化銦之雙極性電晶體中最先進的研究成果。 Abstract The work is aimed for InGaAs/InP double heterojunction bipolar transistors (DHBTs) with high cut-off frequency and high breakdown voltage. The devices are fabricated by an etch-back process, which greatly enhances the yield of small devices. Self-aligned structure and isolation pad technology are also used to reduce the junction capacitance. The high-frequency characteristics of a series of DHBTs with different InGaAs spacer thickness in the composite collector are analyzed in terms of current density and electron saturation velocity. Based on the results of this work, we are able to obtain devices with current-gain cut-off frequency (ft) as high as 255 GHz for a 1x10 μm2 Emitter size, which compares favorably with state-of-the-art devices of the same size.
