Archives:From Germanium to Silicon, A History of Change in the Technology of the Semiconductors
Silicon has been the dominant semiconductor material since the middle 1960s. Today, probably 95% of all semiconductors are fabricated in silicon, yet the first transistor was a germanium device. Until 1960 most design engineers preferred germanium to silicon for computer logic circuits, when, suddenly, germanium was out, and silicon was in. What caused this abrupt shift to silicon? An answer to this question requires some understanding of how and why solid-state scientists went about their research.
This chapter explores the technical choices concerning the use of germanium and silicon as semiconductor materials made by scientists and engineers during the period from 1947, the year the transistor was invented, until 1960 when the design shift from germanium to silicon occurred. During this period, the scientists and engineers at Bell Telephone Laboratories (BTL) were the world's leading investigators of the properties of semiconductors. With few exceptions, scientific research on the transistor was dominated by BTL; from 1947 through 1959, twenty-four of the forty-four papers cited as pioneering papers in semiconductor device technology were written by BTL researchers. The remaining twenty originated from fourteen entities, split evenly between the corporate world and the academic/government complex. In fact, it was not until the end of the 1950s that other industriallaboratories begin to challenge the dominance of BTL in semiconductor research and development. This is in stark contrast with the relatively minor role that BTL and its manufacturing arm, Western Electric, played in semiconductor manufacturing and sales. Through 1958 Western Electric produced 1.315 million transistors,representing less than 2% of the total amount of transistors produced by the semiconductor industry during this period.
In spite of its secondary role as a semiconductor supplier, the course of semiconductor research was shaped by the scientific and engineering achievements at BTL during the 1950s. While most of the semiconductor industry concentrated on manufacturing germanium transistors and diodes during this decade, BTL spent most of its research dollars on silicon devices. This research, coupled with the response by the rest of the industry, led to the development of the surface-stabilized silicon transistor and diode, which in turn signaled the replacement of the commercially dominant germanium by silicon as the leading semiconductor material. In this chapter, I will argue that the precipitating cause for silicon replacing germanium, particularly in computer logic, was the use of a silicon dioxide film to stabilize the surface of silicon semiconductors. This was the most important factor in the development of the planar process, which led first to the dominance of the silicon transistor and then to the integrated circuit.
Citation and Link to Full Article
Philip Seidenberg, “From Germanium to Silicon, A History of Change in the Technology of the Semiconductors,” in Facets: New Perspectivies on the History of Semiconductors, ed. Andrew Goldstein & William Aspray (New Brunswick: IEEE Center for the History of Electrical Engineering, 1997), 35-74.