Pushing the Limits of Piezoresistive Effect by Optomechanical Coupling in 3C-SiC/Si Heterostructure

Abstract

This letter reports a giant opto-piezoresistive effect in p-3C-SiC/p-Si heterostructure under visible-light illumination. The p-3C-SiC/p-Si heterostructure has been fabricated by growing a 390 nm p-type 3C-SiC on a p-type Si substrate using the low pressure chemical vapor deposition (LPCVD) technique. The gauge factor of the heterostructure was found to be 28 under a dark condition; however, it significantly increased to about -455 under illumination of 635 nm wavelength at 3.0 mW/cm. This gauge factor is over 200 times higher than that of commercial metal strain gauge, 16 times higher than that of 3C-SiC thinfilm, and approximately 5 times larger than that of bulk Si. This enhancement of the gauge factor was attributed to the opto-mechanical coupling effect in p-3C-SiC/p-Si heterostructure. The opto-mechanical coupling effect is the amplified effect of the photoconductivity enhancement and strain-induced band structure modification in the p-type Si substrate. These findings enable extremely high sensitive and robust mechanical sensors, as well as optical sensors at low cost, as no complicated nanofabrication process is required.

Photoresponse of a Highly-Rectifying 3C-SiC/Si Heterostructure Under UV and Visible Illuminations

“…Silicon carbide (SiC) is one of the most favorable wide bandgap semiconductor materials owing to its superior mechanical and electrical properties, as well as high resistance to thermal and chemical stress [5], [6]. Among 200 polytypes of SiC, only 3C polytype can be grown epitaxially on a large Si-substrate at around 1000 • C and hence the cost of the wafer reduces significantly [7], [8]. By taking the advantages of silicon-orientated mature MEMS processing technologies, 3C-SiC on the Si structure has opened a new platform to develop a wide range of better and low cost highly sensitive physical sensors for harsh environments.…”

A rapid and cost-effective metallization technique for 3C–SiC MEMS using direct wire bonding

“…[1][2][3] Among the more than 200 poly-types of SiC, 3C-SiC is the most preferable poly-type for MEMS devices as it can be readily grown on a large commercial Si-substrate. 4,5 Hence, the cost of a wafer is reduced signicantly and, most importantly, 3C-SiC is compatible with conventional N/MEMS technologies. 6,7 The proper metallization of any device is very important to obtain exact and accurate responses.…”

Lithography and Etching‐Free Microfabrication of Silicon Carbide on Insulator Using Direct UV Laser Ablation

“…In our previous work, we have reported that the as-grown SiC film on a Si wafer is single crystalline 3C-SiC and its crystallographic orientation is (100) by selected area diffraction (SAD) and X-ray powder diffraction (XRD) measurements, respectively. [15] Due to the mismatch in lattice constant and thermal expansion of SiC and Si, we observed the stacking fault defects at the SiC/Si interface. However, the stacking faults are mainly distributed within 50 nm from the SiC/Si interface and the crystallinity significantly improved with increasing SiC film thickness.…”