Glass passivating method for preparing RF mesa Si diode

Abstract

This invention provides a preparation method of RF desk silicon diode glass passivation with the following steps: a. coating uniformly the prepared glass slurry on the RF desk silicon diode surface b. removing the glass slurry with a scraping knife along the desk surface c drying to form a fluctuated predeposition glass powder layer along the desk surface d. sending samples into a high temperature oven to form preformed glass passive films under the temp of softening glass e repeating the above steps at least on time, finally sending the sample into the high temperature over dealt with heat forming treatment under glass forming temp.

Description

technical field [0001] The invention belongs to the technical field of surface passivation of silicon devices, and is mainly applied to the surface passivation of radio frequency desktop silicon diodes. Background technique [0002] Traditional RF silicon diodes mostly use SiO 2 or SiO 2 -Si 3 N 4 The double dielectric film is used as the surface passivation protection of the device to ensure that the device can work stably and reliably. The glass membrane used is on SiO 2 The basic structure of the membrane—the network structure of the silicon-oxygen tetrahedron is filled with interstitial fixed ions, resulting in a denser microstructure and better resistance to external ionic contamination. The side can form a negatively charged center, which can effectively block the mobile ions on the silicon surface (such as Na + ) electromigration, and because it can be made into a thick film, it has strong performance against moisture and mechanical damage. Therefore, at present...

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Problems solved by technology

The advantage of this method is that it has high precision and can be applied to shallow junctions (such as X j =0.5μm~5.0μm) devices, the disadvantages are high requirements for glass particle size and uniformity, sensitivity to the cleanliness of electrophoretic fluid (referring to ionic contamination), low work efficiency, poor repeatability, and difficulty in forming common Formed film, especially in the case of high table, the glass layer at the top corner of the thermoforming backstage is thin, it is difficult to play a good role in purifying the shallow junction

[0006] 2. Scratch coating method, which is to make a viscous liquid with a certain concentration of glass powder and adhesive, and evenly spread it on the surface of the silicon sample when using it, then scrape the glass on the top of the table with a scraper, and keep the side of the table and the table. Bottom glass, this method has the advantages of simple process operation, good repeatability, and high efficiency. The disadvantage is that the corners of the top of the table are not protected due to shrinkage after the glass powder is sintered and thermoformed. This method is only suitable for deep junction devices (such as deep junction devices) x j =15μm~25μm)

[0007] Before the present invention, the first SiO2 was used in the manufacture of radio frequency desktop high-voltage high-power silicon diodes abroad 2 Passivation protection, and then add the method of scratch coating glass passivation to solve the problem of P at the corner of the high table top + N - However, this method not only requires two different passivation processes, which is complicated, but also the corners of the mesa shrink after the glass powder is sintered and thermoformed, and in some places there is often only SiO 2 Purifying as the glass has shrunk below the shallow junction

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