Optical Power Efficiency Versus Breakdown Voltage of Avalanche-Mode Silicon LEDs in CMOS

Abstract

We report on the dependency of the optical power efficiency η on the breakdown voltage V BR of avalanche-mode (AM) light-emitting diodes (LEDs) in silicon. Lateral p + -n-n + LEDs have been designed in a 65-nm bulk CMOS technology, where V BR is varied between 2 and 9 V. This tunes both the magnitude and the spatial distribution of the reverse electric field, which governs AM electroluminescence. Experiments show that a maximum η of ∼1.7 × 10 −6 is obtained for V BR ∼ 6 V. For V BR < 6 V, non-local avalanche results in a lower η, while for V BR > 6 V, a gradual reduction in η with increasing V BR is obtained. This trend is compared with two recently proposed opto-electronic models. A maximum in η at relatively low voltages is attractive for monolithic opto-electronic integration in silicon.

Optical Sensing of Chlorophyll(in) With Dual-Spectrum Si LEDs in SOI-CMOS Technology

“…Interestingly, Si p-n junction diodes exhibit broad-spectrum electroluminescence (EL) at wavelengths (λ) near 1120 nm in forward mode (FM) and at λ in the range of 400-900 nm in avalanche mode (AM) operation. Although this EL occurs at a low quantum efficiency (∼ 10 −3 -10 −5 ) [20]- [26] due to the indirect bandgap of Si, for many applications the advantages of CMOS integration of the LED outweigh the drawback of low efficiency. Recent advancements [27]- [29] have successfully highlighted the Si LED as a promising candidate for monolithically integrated optical interconnects due to the high responsivity of Si photodiodes (PDs) for wavelengths (λ) < 1000 nm.…”

Optical sensing of chlorophyll(in) with dual-spectrum Si LEDs in SOI CMOS technology

“…The dc power consumption in our LED ranged from 18 mW (I LED = 1 mA) till 118 mW (I LED = 6 mA). For each I LED , an integration time of ∼ 500 ms was used to reduce the noise in measuring the corresponding photocurrent with the SMU, leading to a Yes By switching [19], [20], (this work) ∼ 1100 (forward) bias polarity [24], [26] Si-on-insulator ∼ 1100 10 −3 No Fixed [54] FinFET technology Si nanocrystals 700-900 10 −3 Yes Fixed by [55], [56],…”

“…Interestingly, Si p-n junction diodes exhibit broad-spectrum electroluminescence (EL) at wavelengths (λ) near 1120 nm in forward mode (FM) and at λ in the range of 400-900 nm in avalanche mode (AM) operation. Although this EL occurs at a low quantum efficiency (∼ 10 −3 -10 −5 ) [20]- [26] due to the indirect bandgap of Si, for many applications the advantages of CMOS integration Optical coupling from the Si LED on the CMOS chip to an externally mounted Si PD (reverse biased at 1 V) is measured in presence of a pigmented glycerol droplet (top panel) or a leaf (bottom panel) on top of the LED. The LED is operated in (a) forward mode (FM) and (b) avalanche mode (AM).…”

An Efficient Forward-Biased Si CMOS LED With High Optical Power Density and Nonlinear Optical-Power-Current Characteristic

“…No matter what kind of working mode it is, they all belong to a kind of high-energy light emission mechanism utilizing hot carriers and thus generally demand high operating voltage [4]- [9], which render them unsuitable for application in the very-large-scale integration (VLSI) with a typical voltage of 3.3 V. Many efforts have been carried out to reduce breakdown voltage [14], [15], and improve optical power density and conversion efficiency [4]- [8], [16]- [18]. For example, the lateral p + -n-n + avalanche-mode Si-LED with a breakdown voltage near 6 V was designed [15]. And the enhanced electroluminescent was ever demonstrated through enhanced injection (current density) [16], carrier momentum, and carrier energy engineering [17] with density up to 200 nW•μm −2 .…”