Transistor point-contact

Interface states played a key role in the development of transistors. The initial experiments at Bell Laboratories were on metal/insulator/semiconductor (MIS) stmctures in which the intent was to modulate the conductance of a germanium layer by applying a voltage to the metal plate. However, only - 10% of the induced charges were effective in charging the conductance (3). It was proposed (2) that the ineffective induced charges were trapped in surface states. Subsequent experiments on surface states led to the discovery of the point-contact transistor in 1948 (4). 

In addition to its use as a rectifier, the p—n junction (26) is the fundamental building block for bipolar, junction EFT (fFET), and MOSFET transistors. A thorough understanding of p—n junctions explains much of transistor behavior. The theory (5) of the p—n junction and its role in bipolar transistors was presented within a year of the discovery of the point-contact transistor. 

Considerable interest in the sohd-state physics of sihcon carbide, that is, the relation between its semiconductor characteristics and crystal growth, has resulted from the expectation that SiC would be useflil as a high temperature-resistant semiconductor in devices such as point-contact diodes (148), rectifiers (149), and transistors (150,151) for use at temperatures above those where sihcon or germanium metals fail (see Semiconductors). 

An additional and very attractive aspect of molecular qubits is the fact that they are stable in solution, and that the ligand shell can be functionalized with specific chemical groups. In recent years, this has enabled depositing molecular clusters onto different substrates and grafting them to nanostructures or devices, such as carbon nanotube single electron transistors or point contacts [112]. These devices... 

Germanium photodetectors, 19 137 Germanium point-contact transistor, 9 730-731... 

Point bonding, 27 474, 476. See also Thermal point bonding Point-contact transistor, 9 730-731 Point of departure, 25 244 Point of incipient precipitatioi,... 

Perfection especially is required on the silicon surface. A 100 surface of silicon contains 6.8 x 1014 atoms/cm2. Surface defect densities must be less than one part in 105—105 defects/cm2 for satisfactory MOSFET operation. In fact, the discovery of the original point contact transistor was only possible because the native oxide on single-crystal germanium has surface defect densities less than one part in 104. Good silicon devices required the discovery (10) that the thermal oxidation of silicon could produce an excellent Si—Si02 interface. 

The first prototype transistor (a point-contact semiconductor amplifier ), built by Bardeen and Brattain at Bell Laboratories in 1947 (a), is a far cry from today s silicon chips, packed with miniaturized semiconductor components (6)... 

This quote is from p. 281 of Ref. 46. We comment that point-contact transistors can be easily developed into true negative resistors enabling COP > 1.0 circuits.) The point-contact transistor was simply bypassed by advancing to other transistor types more easily manufactured and with less manufacturing variances. 

Negative-resistor candidates for such a shunt may arise from point-contact transistors, from the Fogal transistor, and from the work of Wang and Chung [45]. 

J. Bardeen, Semiconductor Research Leading to the Point Contact Transistor, in Nobel Lectures, Physics 1942-1962, Elsevier Publishing Company, Amsterdam, 1964. 

The first transistor, made by Bardeen,37 Shockley, and Brattain38 at Bell Telephone Laboratories in 1947, was a point-contact transistor (Fig. 9.17) [18-21],... 

The first transistor, a point-contact transistor, invented by Bardeen, Brat-tain, and Shockley in 1947 [18,19]. Adapted from Terman [5]. 

Even though the field-effect transistor did not come into widespread use until the 1960 s, its invention predated both the junction and point-contact transistors by many years. As it is normal with many innovations, its practical realization was delayed until adequate materials and technologies were available for its fabrication. We can even say that the Thin Film Transistor (TFT) was the first solid-state amplifier ever patented. The basic principle of the field-effect transistor (what we call now JFET) was proposed by the first time by Julius Edgar Lilienfeld as early as 1925 and patented in 1930 Ref (1) (see Fig. la) where an adaptation of the cross section of the... 

Because of their fragility and occasional unreliability, the point-contact electrodes were eventually replaced with three layers of adjacent semiconducting surfaces, each of which corresponded to an element in the triode vacuum tube the emitter layer (for the heated filament which is the source of electrons), the base (for the grid that controls the electron flow), and the collector, for the triode plate that receives the electrons. The areas where the layers join one another are called junctions, and transistors made in this way are known as junction transistors. 

First transistor built (point-contact form) by Bardeen, Brattain, and Shockley of Bell Telephone Labs Junction transistor developed to avoid reliability problems with point-contact transistor... 

In 1947, John Bardeen and Walter Brattain, both research scientists at Bell Telephone Laboratories, while trying to understand the nature of the electrons at the interface between a metal and a semiconductor, made a startling discovery. They found that by making two point contacts very close to one another, they could make a three-terminal device—the first point contact transistor " (see Fig. 4.2). They made the two point contacts at the bottom of a triangular quartz crystal from two strips of gold foil separated by about 50 xm, and pressed it... 

Figure 4.2 The first point-contact transistor. It was invented at Beii Laboratories on December 23, 1947. (Reprinted with permission from Aicatei-Lucent.)...

Transistors eventually made their way into portable radios and other electronic devices, and are most prominently used today as building blocks of integrated circuits. Remarkably, the invention of the point-contact and p-n junction transistors,... 

Since the invention of the point-contact transistor in 1947, the number and variety of semiconductor devices have witnessed a tremendous increase as advanced... 

Fig. 2. A gemianium transistor where B is the base, C, the collector, and 8, the emitter, (a) The external transistor circuit showing the diffusion cloud of minority carriers around the emitter point contact and 1, and and V, are the current and the voltage of the collector and emitter, respectively, (b)...

US physicists John Bardeen, Walter Brattain (1902-87), and William Shockley (1910-89) invent the point-contact transistor. 

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