50-Ω multijunction thermal converters on fused silica substrates

Planar multijunction thermal converters (MJTCs) are in widespread use as standards for ac voltage metrology at frequencies up to 1 MHz. At the National Institute of Standards and Technology (NIST), we are presently using MJTCs based on glassy substrates as standards at frequencies up to 100 MHz. Although these standards have excellent characteristics at high frequencies, one goal for this project is to fabricate excellent MJTCs with 50-Ω input impedances to align with high-frequency ac metrology as commonly practiced. Preliminary results with 50-Ω MJTCs indicate that devices with on-chip input resistors can be successfully fabricated and employed as high-frequency standards.