A New High Sensitivity Illumination and Color Management Photosensor Using Avalanche Photodiode

利用累崩光二極體作為高靈敏度的照明色彩管理光感測器

卓信誠(Shin-Cherng Jwo)

《2008資通技術管理與應用會議》 2008 (2008/12) Pp. 279-287

摘要

本論文利用電漿助長化學氣相沈積法(PECVD)，在玻璃基板上，成功地製造出一種新型結構的漸變能隙超晶格累崩光二極體。依其結構同時驗證此種新的光電檢測元件，具有高靈敏度低雜訊與快速響應速度等特性。超晶格結構是由非晶矽與非晶碳化矽的異質接面所形成的，將載體的游離現象侷限發生於窄能隙的非晶矽上，當載體從寬能隙移至窄能隙時，載體能從此能隙差位，得到動能。因而，能有效地減少撞擊游離起始能量，以此方式，將可增強載體的游離率，得到高光增益與低雜訊特性的元件。 利用光電流倍乘測量法，可得到室溫時，步級能隙與梯狀超品格累崩光二極體的電子與電洞撞擊游離率，這兩種超晶格累崩光二極體的電子對電洞游離率比分別得到為6.4351與6.961，由於梯狀超晶格具有較高的載體撞擊游離效率，故得到較大的游離率比，與較低的雜訊因子，當反向偏壓為20伏特，入射光功率為5微瓦時，步級能隙與梯狀元件的光增益分別為193與225。當負載電阻為1.8仟歐姆時，其交換時間為4.8微秒。此元件的峰值響應波長可隨著所加偏壓與井寬度而變，故可當作照明色彩管理(ICM)光感測器。

關鍵字

照明色彩管理ICM ； 累崩光感測器

並列摘要

In this paper, a new high optical gain amorphous avalanche photodiode has been sucessfully fabricated on ITO/glass substrate by plasma enhanced chemical vapor deposition (PECVD). All of these superlattice (SL) structures are made of an a-Si/SiC: H hetrojunction to spatially confine the carrier ionization events within the narrow bandgap material (a-Si: H). As the carriers move across the heterobarrier step, they gain kinetic energy from the band edge discontinuity thus effectively reducing the impact ionization threshold energy. In this way each carrier will impact ionize a new electron-hole pair and the ionization rate can be enhanced. The performance of high gain, high sensitivity, and low noise can be achieved. Due to the multiplication mechanism in the Si/SiC: H layer, the optical gain will be enhanced. For step-gap and staircase SAPD, the room-temperature electron and hold impact ionization rates, α and β, have been determined by the photocurrent multiplication measurements. The ratios of two kinds of SAPD are 6.4351and 6.961at a fixed electric field, respectively. Avalanche multiplication in the SL layer yields a high optical gain of 193(225) at a reverse bias V(subscript R)=20V, and an incident light power P(subscript in)=5μW step-gap (staircase) SAPD. These devices operated in reverse mode can be used as an illumination and color management (ICM) photosensor.

並列關鍵字

Illumination and Color Management ICM ； Avalanche Photodiode