Estimates of the Photo-Response Characteristics of a Non-Fully-Depleted Silicon p-i-n Photodiode for the Near Infrared Spectral Range and the Experimental Results

We have estimated the responsivity and the rise time of a non-fully-depleted silicon p-i-n photodiode. The estimate of the rise time was done by considering the undepleted intrinsic layer resistance and the drift velocity at low electric field. Our research shows that there exists an optimum intrinsic layer resistivity for the fastest photo-response characteristics at a given condition. The maximum responsivity is 0.72 A/W and the fastest rise time is 14 ns for a 24-V operation voltage at a 900-nm wavelength when an 80-pm depletion width is formed on a high-resistive, n-type wafer of 380 mu m in thickness. Based on our considerations, we fabricated a high-performance silicon p-i-n photodiode for near IR measurement and analyzed its characteristics. In spite of the optical loss caused by the IR filter, the responsivity for a 900-nm wavelength was 0.67 A/W, and the rise time was about 20 ns at 24 V. These values were well consistent with our estimates when are considered the parasitic capacitance caused by the package, and were excellent compared with those from conventional photodiodes.