Injection-Avalanche-Based n⁺pn Silicon Complementary Metal–Oxide–Semiconductor Light-Emitting Device (450–750 nm) with 2-Order-of-Magnitude Increase in Light Emission Intensity

Abstract

In this paper, we report on an increase in emission intensity of up to 10 nW/µm2 that has been realized with a new novel two junction, diagonal avalanche control, and minority carrier injection silicon complementary metal–oxide–semiconductor (CMOS) light emitting device (LED). The device utilizes a four-terminal configuration with two embedded shallow n+p junctions in a p substrate. One junction is kept in deep-avalanche and light-emitting mode, while the other junction is forward biased and minority carrier electrons are injected into the avalanching junction. The device has been realized using standard 0.35 µm CMOS design rules and fabrication technology and operates at 9 V in the current range 0.1–3 mA. The optical output power is about one order of magnitude higher for previous single-junction n+p light-emitting devices while the emission intensity is about two orders of magnitude higher than for single-junction devices. The optical output is about three orders of magnitude higher than the low-frequency detectivity limit of silicon p–i–n detectors of comparable dimensions. The realized characteristics may enable diverse optoelectronic applications in standard-CMOS-silicon-technology-based integrated circuitry.

Low power wide spectrum optical transmitter using avalanche mode LEDs in SOI CMOS technology

“…(1)) is estimated to be about 1.4 × 10 −5 , comparable to what was also reported for Si earlier [22]. Using IQE and n TE (section 3), the total coupling quantum efficiency of the link (η system ) is estimated as 4 × 10 −9 .…”

“…This work successfully demonstrates a low power wide spectrum optical transmitter in CMOS technologies that can be integrated with standard Si detectors. It further reinforces the promise of enabling AMLEDs as light sources for Si CMOS technology for monolithic integration of optocouplers in CMOS [5,10,11,22]. …”

Monolithic optical link in silicon-on-insulator CMOS technology

“…3(a). The IQE of Si AMLEDs is reported to be ∼ 10 −5 [12]. Figure 9 shows the measured η versus I AMLED for different values of D. Note that a heat sink is present in these designs.…”

“…Operating a Si LED in avalanche mode (AM) yields broad-spectrum EL (λ ∼ 350-900 nm) [10][11][12][13] with a reported IQE of ∼ 10 −5 [12]. This EL spectrum has a significant overlap with the spectral responsivity of Si (PDs) [8] resulting in a high IQE of the PD.…”

The Avalanche-Mode Superjunction LED

“…The electro-luminescence in avalanche-mode (AM-EL) is governed by impact ionization [10] and hence, by the reverse electric field F [11]. The main challenge, however, has been the relatively lower radiative efficiency of AMLEDs (∼10 −5 ) [3] as compared to that of forward biased LEDs (∼10 −3 ) [12], which can be compensated by integrating them with single photon avalanche diodes (SPADs) [13] as detectors, which are sensitive to a few photons. Nevertheless, higher optical emission intensities are desired in AMLEDs because the attainable bandwidth of optical links is critically dependent on the EL-intensity of the LED [14].…”