A performance/cost approach to transistor design

The customer is interested in the overall performance and the cost of transistors and this requires a more sophisticated design approach aimed at high performance at low cost. For the high-frequency high-power market, the transistor designer is technically limited in his choice of junction formation methods, and the cost of products is high. For those markets where many techniques compete, the performance/cost design approach is essential; the low-frequency low-power market particularly warrants this approach at this time. For the low-frequency low-power market, where several techniques can yield the same performance, the designer must consider the various methods of forming junctions and making contacts, and the mechanical design, including the housing, in terms of the cost factors. The various design elements will be described and analysed with respect to the cost factors reflected by process complexity, product reproducibility and design flexibility. Particular emphasis is placed on a comparison of the three basic junction-formation techniques¿alloy, grown and diffused. This analysis indicates, on a performance/cost basis, that alloy and grown types of transistors have, and will have for many years, an important share of the computer, audio and broadcast radio-frequency and intermediate-frequency markets. Consideration of the high-frequency high-power markets, and the inevitable simplification of the relatively new diffusion process, leads to the conclusion that all three basic techniques will be required to obtain the broadest market coverage in the expanding transistor market.