Predictive Reliability Model of 10G/25G Mesa-Type Avalanche Photodiode Degradation

Abstract

Avalanche photodiodes (APDs) are important building blocks for high-sensivity, low-noise receivers deployed in the datacenter, wireless and cloud computing networks. Maintaining stable dark current is a crucial task for overall robust sysem reliability. To achieve design-in low dark current stability, good knowledge of reliability physics is indispensable. In this work, we study the physical mechanisms of 10G/25G mesa-type APD degradation. We institute a predictive reliability model to account for the degradation processes. A comprehensive comparison of APD and IC transistor is also illustrated in terms of dielectric breakdown, mobile ion migration and hot carrier injection. The model suggests that surface leakage current is the dominant factor for the mesa-type APD degradation. Based on the model, it is predicted that highly reliable 10G/25G APD can be achieved with the suppression of weak links at the surface/interface states.

Humidity Degradation Study of Mesa-type Avalanche Photodiodes under Harsh Environmental Stresses

“…The APD device was based on mesa structure with coplanar P-and N-metal contacts to enhance the speed and reduce the series resistance . The top P-mesa consisted of InGaAs contact layer and InP window (Huang et al, 2016). The p-InGaAs contact layer was covered by the p-metal to form Ohmic contact and connected to the bondpad by a p-metal ring that surrounded the circular anti-reflective (AR) window.…”

“…By taking the square root of the ratio of humidity coefficient of mesa-type versus planar-type APD, the humidity sensitivity of the mesa-type is estimated to be higher than that of the planar-type by a factor of 1.7. This is expected because the mesa-type structure is likely to generate more weak spots resulting from surface state, geometrical non-uniformity, and topography (Huang et al, 2016;.…”

Nanoscale III-V Semiconductor Photodetectors for High-Speed Optical Communications

“…(3) Geometry inhomogeneity For electronic IC, the geometry inhomogeneity may induce current crowding and cause early reliability failure [67][68][69]. For APD, the inhomogeneous structure is typically generated by mesa etch [70][71][72]. The etched mesa interface may cause an increase in leakage current due to the generation of surface state [70,71].…”

Influences of contact electrode shape and incidence direction on p‐i‐n photodiodes

“…As far as we know, the currently reported photodetectors still have some with a ring contact metal electrode covered on top of the device [10][11][12][13][14]. This study analyses the influence of the contact electrode shape on p-i-n PD performance, and the PDs with ringcovered p-contact electrode (RCC-PD) and fully-covered p-contact electrode (FCC-PD) were prepared and measured.…”