Microwave, photonic, and power applications generally employ discrete devices. For example, .an IMPATT diode is used as a microwave generator. an injection laser as an optical source. and a thyristor as a high-power switch. However. most electronic systems are built on the integrated circuit. which is an ensemble of both active (e.g.. transistor) and passive (e.g., resistor, capacitor, and inductor) devices formed on and within a single-crystal semiconductor substrate and interconnected by a metallization pattern. ICs have enormons advantages over discrete devices connected by wire bonding. The advantages include (a) reduction of the interconnection parasitics, because an IC with multilevel metallization can substantially reduce the overall wiring length: (b) full utilization of a semiconductor wafer 's area, because devices can be closely packed within an IC chip; and (c) drastic reduction in processing cost, because wire bonding is a time-consuming and error-prone operation.
This chapter discusses combinations of the basic processes described in the previous chapters to fabricate active and passive components in an IC. Because the key element of an IC is the transistor, specific Processing sequences are developed to optimize its' performance. The chapter considers three major IC technologies associated with the three transistor families: the bipolar transistor, the MOSFET, and the MESFET. in addition, it discusses the fabrication of microelectromechanical systems by micromachining techniques, Specifically, it covers the following topics:
• The design and fabrication of IC resistors, capacitors, and inductors
• The Processing sequence for Standard bipolar transistor and advanced bipolar devices
• The Processing sequence for MOSFETs, with special emphasis on CMOS and memory devices
• The Processing sequence for high-performance MESFETs and monolithic microwave ICs
• The major challenges for future microelectronics, including ultrashallow junction, ultrathin oxide. new interconnection materials. low power dissipation, and isolation
• Microelectromechanical systems formed by orientation-dependent etching, sacrificial etching, or LIGA (lithography, electroplating, and molding) processes
• the simulation of IC fabrication processes using SUPREM
figure 9.1 illustrates the interrelationship between the major process steps used for IC fabrication. Polished wafers with a specific resistivity and orientation are used as the starting material. the film formation steps include thermally grown oxide films (Chapter3) .and deposited polysilicon, dielectric, and metal films (Chapter 8). Film formation is often
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