The formaldehyde detection is important for protecting human health and controlling environment pollution. Many metal oxide sensors have been developed for the formaldehyde detection in the last decade. The NiO sensor is considered as the most sensitive one, which is able to detect very low concentration of formaldehyde (<1 ppm). But it needs a high operating temperature. Presently, graphene has attracted much attention for sensor applications. Its high surface-to-volume ratio possesses the potential ability to detect the presence of a single interacting molecule and its high carrier mobility ensures low electrical noise and low power consumption. However, pristine graphene is chemically inert and shows weak adsorption of formaldehyde molecules. To obtain stronger adsorption ability, thereby a higher sensitivity, it is necessary to functionalize or pretreat graphene. In this study, we design a new hybrid sensor, in which graphene acts as a highly conductive network and NiO as a sensitive layer for formaldehyde. This hybrid sensor combines the advantages of both materials. Comparing to the pure graphene sensor and the usual NiO sensor, the hybrid sensor demonstrates better sensing performances, such as faster response and recovery, importantly, operating at room temperature. This sensor could be easily integrated with complementary metal oxide semiconductor (CMOS) chip in the future.
Multifrequency test can maximize differences between the failure state and the normal state of the analog circuit's response,and Neural Networks(NNs)have the ability to solve complex classification problems.An efficient approach for diagnosing faults in analog circuits is presented.It is based on the advantages of both multifrequency test and NNs.The sensitivity analysis is used to generate and choose the multifrequency test vectors of the Circuit Under Tes(tCUT).Fault features of the test point in CUT are extracted and fused.NNs are used to classify the features in a variety of state for the detection and location of faulty components in CUT.The experimental results show that this method is very effective and highly practical for fault diagnosis of analog circuits.
In order to improve the total dose radiation hardness of the buried oxides (BOX) of separation by implanted oxygen (SIMOX) silicon on insulator (SOI),we implanted silicon into the BOX at a dose of l times 1015cm-2 and then annealed at 800 degC in N 2 ambience. Partially depleted CMOS/SOI inverters with enclosed-gate structure fabricated on improved SIMOX substrate and standard SIMOX substrate were exposed to 60CO gamma-ray radiation. The results of demonstrate that compare to standard CMOS/SOI inverters; the improved CMOS/SOI inverters have less switching voltage shifts and smaller leakage current after the same total dose irradiation
It was found that cubic CoSi2, tetragonal alpha-FeSi2 and orthorhombic NiSi films formed by the solid state reaction of metal films and single crystal Si(100) substrates are textured. The polycrystalline films consist of grains in which certain crystallographic planes align preferentially with (110)-type planes of Si, leading to all off-normal fiber-like texture.
The properties of the native oxides on GaAs-based materials have been characterized. The n-channel depletion-mode GaAs MOSFETs with the liquid phase oxidized gate have been fabricated and characterized. The primary results show the stability and potential of the liquid phase oxidation method for application to GaAs-based devices. In addition, a new planarized shallow trench isolation technique, a simple self-align process and an oxidized AlGaAs gate for GaAs-based device applications using liquid phase oxidation method have been demonstrated.
本文报导了一种解决氧化锡气体敏感膜龟裂问题的有效方法.实验中发现,溅射形成的氧化锡薄膜在高温处理后或在长时间的高温工作中会发生龟裂,对器件的稳定性和可靠性带来很大影响.我们用两种方法解决了这个问题.一个是用磷硅玻璃(PSG)回流对氧化锡衬底的粗糙表面进行平坦化处理,另一个是把氧化锡薄膜图形设计成许多细长条状,以释放高温引起的应力变化.这种技术也适用于其它薄膜产生的微裂问题.
