On the effect of delta-doping in self-switching diodes

Lowering the carrier concentration is presented as a way to considerably improve the performance of self-switching diode (SSD) detectors. A physics-based theoretical model was used to derive an expression for the responsivity of SSDs as a function of carrier concentration, mobility, and design parameters. Monte Carlo simulations confirmed the modeled effect of varying carrier concentration and channel width. SSDs were fabricated in InAs heterostructures with different delta-doping levels. Radio frequency (RF) characterization at 50 GHz reproduced the modeled trends. By reducing the carrier concentration in InAs SSDs with 40 nm wide channels from 2.7 x 10(12) cm(-2) to 1.5 x 10(12) cm(-2) (-44%), the noise equivalent power (NEP) improved from 130 pW/Hz(1/2) to 87 pW/Hz(1/2) (-33%)