Micro hotplate of silica-based structure and preparation method thereof

Abstract

The invention discloses a micro hotplate of a silicon-based structure and a preparation method thereof, a substrate of the micro hotplate is a monocrystalline silicon of which crystal orientation is (100), a surface of the substrate is orderly coated with a porous silicon layer, a thermal isolation layer and a heating area from inside to outside, the thermal isolation layer is a silicon dioxide layer, and the heating area is a Pt electrode, wherein the back of the substrate and the porous silicon layer are corroded into a pit. For the micro hotplate provided by the invention, on the basis of original corrosion, the porous silicon layer in the middle is further corroded. A contact area of the corroded thermal isolation layer with the air is increased, since the air has poor heat conductingproperty, heat of a work area can be effectively prevented from losing to a silicon base; the newly designed indirectly heated Pt electrode can concentrate heat effectively in the work area, and thus,working efficiency is improved. The preparation method is low-cost, steady in processing technology and easy for batch production.

Description

technical field [0001] The invention belongs to the field of semiconductor sensors, and in particular relates to a silicon-based micro-hot plate and a preparation method thereof. Background technique [0002] While the rapid development of industry has brought considerable benefits, it has also caused pollution to the environment. Harmful and toxic gases emitted by factories are always endangering the ecological environment and human health. In personal homes, flammable and explosive gases also pose a threat. The gas sensor is an electronic nose that can detect toxic and harmful gases in the air and convert the detected gas composition and concentration into electrical signals. Widely used in chemical industry, environmental detection, disaster prevention and alarm, etc. [0003] In recent years, microelectromechanical systems (MEMS) technology has been vigorously developed. The application of MEMS technology on sensors is a research hotspot at home and abroad. Compared...

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Problems solved by technology

However, the direct heating type heating layer has the following disadvantages: firstly, there is an influence between the signal circuit and the heating circuit; secondly, the expansion and contraction of the device after heating may easily cause poor contact

[0007] CN 203998937U discloses a MEMS silicon-based micro-hot plate. On the basis of the above-mentioned patents, the micro-hot plate adopts a layer of porous silicon layer formed on the surface of the silicon substrate, and a layer of silicon dioxide film is covered on the porous silicon layer. As a thermal insulation layer, it has a better thermal insulation effect, but it does not solve the defects of the direct heating layer

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