Semiconductor devices protection

Because of the high functional values that polyimides can provide, a small-scale custom synthesis by users or toU producers is often economically viable despite high cost, especially for aerospace and microelectronic appHcations. For the majority of iudustrial appHcations, the yellow color generally associated with polyimides is quite acceptable. However, transparency or low absorbance is an essential requirement iu some appHcations such as multilayer thermal iusulation blankets for satellites and protective coatings for solar cells and other space components (93). For iutedayer dielectric appHcations iu semiconductor devices, polyimides having low and controlled thermal expansion coefficients are required to match those of substrate materials such as metals, ceramics, and semiconductors usediu those devices (94). 

Protection from such surges is tichieved by using a distribution class surge arrester at the receiving end of the supply. Generally no protection is therefore necessary for the semiconductor devices. For more details see Chapter 18. 

This is applicable to thyristor (SCR) circuits to protect all the semiconductor devices used in the switching circuit, such as diodes (also power diodes) or IGBTs, in addition to SCRs. The same protection can be applied to all the semiconductor circuits likely to experience high dv/di. 

The role of SCRs is to vary the supply parameters, which require frequent changes in V, i.e. du/df and in /, i.e. di/di in an energized condition. Becau.se of momentary phase-to-phase short-circuit, dv/di occurs during switching OFF and d 7df during switching ON sequences. Both are transient conditions and may damage the semiconductor devices used in the circuit. To protect the devices, the transient conditions can be dealt with as follows ... 

The present chapter deals with the CVD of metals and some metal alloys and intermetallics. The metals are listed alphabetically. The range of applications is extensive as many of these materials play an important part in the fabrication of integrated circuits and other semiconductor devices in optoelectronic and optical applications, in corrosion protection, and in the design of structural parts. These applications are reviewed in greater depth in Chs. 13 to 19. 

A.2 Semiconductor Device Fabrication. In this section we investigate the gas-phase synthesis of compounds, primarily semiconductors, that are preferentially deposited on a surface to form a layer called a thin film. This technology can be used to form structural and protective layers of materials described in the previous section, but is used primarily to form thin films from semiconductor materials for electronic devices. Recall from Figure 6.99, for example, that most semiconductor devices are made from layers of appropriately doped compounds. In order to fabricate these devices at ever smaller scales, the layers must be formed in a carefully controlled manner. This... 

Silicon Dioxide. Si02 layers produced by PECVD are useful for intermetal dielectric layers and mechanical or chemical protection and as diffusion masks and gate oxides on compound-semiconductor devices. The films are generally formed by the plasma-enhanced reaction of SiH4 at 200-300 °C with nitrous oxide (N20), but CO, C02, or 02 have also been used (238-241). Other silicon sources including tetramethoxysilane, methyl dimethoxysilane, and tetramethylsilane have also been investigated (202). Diborane or phosphine can be added to the deposition atmosphere to form doped oxide layers. 

All books, reviews, and entries on CPs describe the potential applications. Chandrasekhar and others ° have reviewed in comprehensive fashion the applications of CPs, including batteries sensors electro-optic and optical devices microwave- and conductivity-based technologies electrochromic devices electrochemomechanical and chemomechanical devices corrosion protection semiconductor, lithography, and electrically related applications— photovoltaics, heterojunction, and photoelectrochemical cells capacitors electrolytic and electroless metal plating CP-based molecular electronic devices catalysis and delivery of drugs and chemicals membranes and LEDs. 

Typical physical properties obtainable with UV cured silicones are provided In Table I. Incorporation of reactive unsaturation into the silicone polymer backbone In combination with a photosensitization system provided the photocure capability. Properties of a standard heat-cured encapsulant developed for use on semiconductor devices, Dow Corning HIPEC R-6103, are provided for comparative purposes. Clearly, introduction of a photocrosslinking mechanism into a siloxane type composition has afforded the desired result. The one-part, solventless, UV curable silicone composition cured rapidly upon exposure to UV radiation, providing a cured composition which has retained the typical properties that make silicones so attractive for protection of semiconductor devices. 

The objective of this chapter is to illustrate the use of microradiology with coherent x-rays [ 1 ] to investigate open problems in electrodeposition. Metal electrodeposition is an old and widely exploited technique, one of the most frequently used for protective and decorative coating [2], semiconductor device fabrication processes, and other industrial tasks [3,4],... 

Gallium arsenide is an important semiconductor and crystallizes with a zinc blende lattice (see Figure 5.18b). Slow hydrolysis occurs in moist air and protection of semiconductor devices from the air is essential N2 is often used... 

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