Optimizing SCR Design for Optical Detection
Abstract
Though traditionally used as switching devices, thyristors are capable of facilitating the conversion of light intensity to frequency. However, off-the-shelf thyristors are designed to handle relatively large current (> 1 mA) and are therefore not suitable for low-power light detection. In this work, low current (< 1 nA) thyristors were fabricated using the AMI ABN process via MOSIS based on a previous design that was slightly modified. The fabricated thyristors as well as the transistors that were included for verification purposes were characterized with an Agilent 4155B Semiconductor Parameter Analyzer. The fabricated thyristors exhibited the expected switching behavior and operated with current levels in tens of pA. Measured I-V characteristics of the transistors revealed that the exclusion of an active mask even within the pbase layer when using the AMI ABN process results in suboptimal performance. An analysis of the thyristors corroborated this finding and confirmed simulation results in previous work that indicate that the thyristor switching voltage decreases in direct proportion to the width of the first n doped layer. Incident light was also found to cause a decrease in switching voltage. From these findings, the optimal width of the first n doped layer was determined to be equal to or greater than 5.2 um, and the active mask was recognized as an essential augmentation to all metal contacts in devices fabricated using CMOS technology.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2009
- Accession Number
- ADA501706
Entities
People
- Esperanza C. Del Casal
Organizations
- Naval Postgraduate School