在本論文研究中，我們提出一個分離式吸收、電荷、增益之異質接面光電晶體。當元件在不犧牲增益特性之下，在磊晶時插入倍增層InAlAs，操作在近崩潰區時，可以大大的減少電子在基-射接面被困住的時間，同時又可產生高輸出頻寬。增益輸出主要是由光導電體和崩潰兩個機制增益(gain)在交互作用，而不用操作高於30 V以上的逆向偏壓，又可得到大於104高增益。元件操作逆向偏壓6 V時，可達到高輸出頻寬(1.6 GHz)以及非常極大高增益頻寬積(90 THz) 第二，我們又提出了以一個標準的矽基板做成垂直入射的衝渡二體(IMPATT-PD)且操作在830 nm波段有著高速的表現。藉由頻寬共振的效應來改善傳統Avalanch Photodoide(APD)增益頻寬積互相抵換(Trade-off)的問題和矽基板吸光所產生的擴散電流。根據我們元件的模擬和量測結果，與傳統的衝渡二極體非常相似，當逆向偏壓加大，共振頻率也隨著變大。而在不使用Silicon-on-Insulator(SOI)這個昂貴的技術且增益為一的時候外部效率是60 %，可以達到頻寬為(30 GHz)的超高增益頻寬積(690 GHz)，同時通過標準規格OC-192，清楚的看到在10 Gbit/s眼圖有開。 In this thesis, we demonstrate a high-performance heterojunction phototransistor (HPT): separate-absorption-charge-multiplication HPT (SACM-HPT). The incorporation of an In0.52Al0.48As based multiplication layer in the In0.53Ga0.47As based collector layer of our HPT allows for a great shortening of the trapping time (~ns to ~30 ps) of electrons at the base-emitter junction under near avalanche operation, without sacrificing the gain performance. The interaction between the photoconductive gain and avalanche gain means that it is not necessary to use high bias voltages (>30 V) in our device to attain high-gain (>1×104 ) performance. With this device design, we can achieve an extremely high (90THz) gain-bandwidth product (1.6GHz, 5.5×104 ) under a 6 V bias. Second, we demonstrate a high-speed Si/SiGe based vertical-illuminated Impact Ionization Avalanche Transit Time Photodiode (IMPATT-PD) on the standard Si substrate operating in the 830nm wavelength regime. The studied andwidth-enhancement (resonant) effect can greatly release the trade-off between gain and bandwidth performance of a traditional APD and screen the slow diffusion current from Si substrate. According to our modeling and measurement results, the extracted internal resonant frequency significantly increases with the reverse leakage current (bias voltage), which is similar to the behavior of a traditional IMPATT diode. By properly choosing the bias voltage, a wide 3-dB bandwidth (30GHz), ultra-high gain-bandwidth product (690GHz) with a 60% external efficiency at unit gain, and a clear eye-opening at 10Gbit/sec, which can pass the OC-192 eye masks, can be achieved simultaneously in our device without using costly silicon-on-insulator (SOI) substrate.
