近來，我們開發850奈米垂直共振雷射(VCSEL)高可靠度高速(>25Gbit/sec)及窄光譜寬度和低功率損耗，主要有兩個重要的製程步驟，第一是鋅擴散第二是水氧化步驟，用來侷限光場及電流侷限在我們VCSEL架構上。而要在P-DBR得到好的鋅擴散輪廓，需要品質好的氮化矽薄膜，所以我們在不同的電漿氣象沉積機台做了不同的實驗來得到所要求的薄膜。關於水氧化實驗，主要問題是氧化孔大小的在晶圓上的均勻性，我們使用自製的水氧化系統做了測試，在3.5cm×3.5cm的範圍下所得到的誤差值為正負0.75um是相當好的均勻性。 我們開發獨特的製程架構及高品質850nm VCSELs晶圓，主要改變是將磊晶層成長在半絕緣基板上，及較短的共振腔(0.5)和再主動層加入了應力(15%)，達到低操作電流(7.92 kA/cm2)和低能量數據傳輸比(EDR:224fJ/bit)，以證明850奈米VCSEL在85 ℃的操作下可達到>41Gbit/sec傳輸，這成就將導致數據中心的通信蓬勃發展在市場上產生強烈衝擊。 ;In this work, we develop key steps for the mass production of high-reliability, high-speed (> 25 Gbit/sec), narrow spectral width, and low power consumption 850 nm vertical-cavity surface-emitting laser (VCSEL). There are two main unique fabrication steps of our VCSELs. One is Zn-diffusion and the other is wet-oxidation (relief) for optical and current-confined apertures in our VCSEL structure, respectively. In order to get well-controlled Zn-diffusion profile in the DBR layers of VCSEL to manipulate the number of optical modes inside cavity, a high-quality Si3N4 film has been developed by using different CVD systems and implemented in the device fabrication processes. Regarding with the wet-oxidation process, its major concern is in the uniformity of the aperture size across the whole wafer. A home-made wet-oxidation system has been developed to meet such challenge and a good uniformity (±0.75um) in the fabricated VCSEL wafers with (3.5cm×3.5cm) area has been demonstrated. By use of the well-developed unique fabrication processes and high-quality 850 nm VCSELs wafers grown on semi-insulating GaAs substrate with short-l (0.5 ) cavity structure and highly strain active layers (15%), record low driving current density (7.92 kA/cm2) and record low energy to data rate ratio (EDR: 224fJ/bit) has been demonstrated for > 41 Gbit/sec operation of 850 nm VCSEL from room-temperature to 85 ℃ operations. This achievement would result in strong impact on the booming market of communication in data center.
