A three-terminal silicon-based light emitting device is proposed and fabricated in standard 0.35 μm complementary metal-oxide-semiconductor technology.This device is capable of versatile working modes:it can emit visible to near infra-red (NIR) light (the spectrum ranges from 500 nm to 1000 nm) in reverse bias avalanche breakdown mode with working voltage between 8.35 V-12 V and emit NIR light (the spectrum ranges from 900 nm to 1300 nm) in the forward injection mode with working voltage below 2 V.An apparent modulation effect on the light intensity from the polysilicon gate is observed in the forward injection mode.Furthermore,when the gate oxide is broken down,NIR light is emitted from the polysilicon/oxide/silicon structure.Optoelectronic characteristics of the device working in different modes are measured and compared.The mechanisms behind these different emissions are explored.
Low-voltage silicon(Si)-based light-emitting diode(LED) is designed based on the former research of LED in Si-based standard complementary metal oxide semiconductor(CMOS) technology.The low-voltage LED is designed under the research of cross-finger structure LEDs and sophisticated structure enhanced LEDs for high efficiency and stable light source of monolithic chip integration.The device size of low-voltage LED is 45.85×38.4(μm),threshold voltage is 2.2 V in common condition,and temperature is 27 ℃.The external quantum efficiency is about 10-6 at stable operating state of 5 V and 177 mA.
Silicon-on-insulator(SOI) substrate is widely used in micro-electro-mechanical systems(MEMS).With the buried oxide layer of SOI acting as an etching stop,silicon based micro neural probe can be fabri-cated with improved uniformity and manufacturability.A seven-record-site neural probe was formed by inductive-coupled plasma(ICP) dry etching of an SOI substrate.The thickness of the probe is 15 μm.The shaft of the probe has dimensions of 3 mm×100 μm×15 μm with typical area of the record site of 78.5 μm2.The impedance of the record site was measured in-vitro.The typical impedance characteris-tics of the record sites are around 2 MΩ at 1 kHz.The performance of the neural probe in-vivo was tested on anesthetic rat.The recorded neural spike was typically around 140 μV.Spike from individual site could exceed 700 μV.The average signal noise ratio was 7 or more.
