Research Of Si-based Light Emitting Device Fabricated In Standard CMOS Process

As a most promising next-generation product which may take place of traditional microelectronic integrated circuit,Si-based optical interconnection system is getting increasing attention.Because of indirect band gap,silicon is inefficient as a light emitting device,and this becomes a serious problem for full-silicon optoelectrical integarted circuits.In this paper,based on deep sub-micron VLSI technology,we make a deep study in silicon-based light emitting device(Si-LED),and a novel efficient Si-LED is fabricated.The highlights of this work are1)As the breakdown voltage of silicon p-n junction is too high to be compatible with other devices in recent standard CMOS process,it is interesting to develop forward-biased Si-LED for low-voltage operation.However,the effects of charge carrier,current density and interface structure on light emission in forward-biased diode need to be investigated.2)The novel wedge-shaped monocrystalline Si-LED and Si-LED array,the polycrystalline silicon PIN-LED,and a simple optical interconnection structure consisting of polycrystalline silicon PIN-LED and monocrystalline Si-LED,are designed and fabricated by UMC 0.18 ?m 1P6 M CMOS process.3)The electrical properties and optical properties of above-mentioned Si-LED are tested.Knowing the physical mechanisms for light emission by their spectrums,it is interesting to investigate the current dependence of light emission in our test devices.The measurement results indicate that the emission spectrum of the device with eight-petal configuration located at near-IR region,whose peak wavelength is around 1130 nm.And the device's optical power increases to 1200 n W without saturation at 2.1 V@200 mA.The maximum power conversion efficiency reaches up to 5.8×10-6 at 1.2 V@40 mA,which is superior to the reported experimental result.Due to the features of low operating voltage and high conversion efficiency,the device is highly attractive for future optoelectronic applications.4)The measurement results of optical interconnection structure indicate that monocrystalline Si-LED light detector can operate most efficiently at the voltage of-2.5 V,and its light current increased with the increasing injection current of polycrystalline silicon PIN-LED,so this structure can achieve the basic function of optical interconnection.