Can the the Junction Field Effect Transistor (JFET) a discrete semiconductor device that dramatically changed the electronics industry in the 1960s, do it again? In the 1960s, the JFETs small size, low cost and very low power consumption made portable electronic systems possible. No longer would the world need to use very large and power hungry vacuum tubes to build computers, electronic instruments, radios, satellites, space ships or medical equipment. Just like today’s modern chips, the JFET opened up a new era of consumer and industrial based applications, that resulted in the birth of multinational electronic corporations like Teledyne.
Today the classical silicon JFET is more of an aftermarket product. However, SiC JFETs are on the move upward. This is primarily because of its applications in high-power and high-temperature applications.
JFET History
Although the first patents for the JFET were in the 1920s, the JFET, from all indications, was not commercially manufactured until the 1960s. A company named Amelco gets that credit. Its JFETs were designed into hybrid op amps, effectively the first JFET op amp, and the first JFETs to go to the moon. Amelco does continue on through history, effectively becoming one of the many company building blocks that formed Teledyne Semiconductor. Teledyne in the 1970s began marketing its FeTRON technology as a direct replacement for vacuum tubes. One of selling points of JFETs based electronic systems, besides the power and size, included reliability, lower heat dissipation, and maintenance. Electronic systems based on vacuum tubes at the time had to tuned on a regular basis to operate correctly. The JFET was also noted as having better IV curved thant than the vacuum tube, all with very high input impedance, something the bipolar transistor, the JFET’s direct discrete competitor at the time, didn’t.
The JFET Today
Today the JFET exists both in discrete form and within monolithic analog integrated circuit chips. chip, specifically op amps. Some of the largest semiconductor companies today, like Texas Instruments and OnSemi offer hundreds of JFET discrete devices. . As well, much smaller companies, like InterFET, Calogic. Central Semiconductor, Linear Integrated Systems also offer an array of discrete JFET devices.
Estimating the size of today’s JFET market is complicated. Different market research firms take different approaches. Because JFETs are integrated into op amp chips, sold by companies such as Analog Devices, some market research firms calculate JFET market size as the sum of discrete JFET sales and the sum of monolithic integrated circuits that incorporate JFET technology. That’s an important point. However, when looking at the JFET market, one has to remember that JFET op amps compete against discrete JFETs.
In order to fully ascertain and understand the details of the JFET market it is important to understand and get involved with the JFET supply chain. Find below a list of JFET and JFET supply chain companies. These companies offer discrete JFETS, JFET packaging and wafer fabrication services as well as design services.. It is also important if you want to enter the JFET market, you need JFET discrete products, or want to integrate JFET technology into ASIC chip solutions to become familiar with the people that operate these companies. Disruptions in the JFET supply chain can effect business plans. The JFET market is a thin market .This means that sudden changes in demand can effect the ability for companies that depend on discrete JFETs discrete to experience unexpected disruptions in product deliveries as a result of large orders from system manufacturers and sudden changes in vendor loyalty.
Table One; The JFET Supply Chain, International Manufacturers and Suppliers List
Texas Instruments JFET Page: JFET At this link find Texas Instruments JFET transistors, JFET boards, JFET simulation models and simulation tools. Texas Instruments separates itself from other JFET vendors in that it offers free SPICE simulator and JFET spice models to support its JFET design community.
ON Semiconductor JFET Page: At this link find OnSemi’s JFET transistors search results.
Calogic JFET Page : At this link find Calogic’s JFETs used for amplifiers, switches and diodes.
InterFet JFET Home: InterFET bills itself as the largest supplier of JFETs in the world. The company as well as its online JFET database indicates that it has the largest selection of JFETs for applications like switches, amplifiers, oscillators, diodes and more.
NXP Semiconductor JEFT Page : This link indicates that NXP Semiconductor has about 18 JFET devices available.
Vishay JFET Page: Vishay, a publicly traded company reports that it still has a limited supply of JFETs available. At this link find Vishay’s JFET application notes and JFET contact information. One ap note discusses JFET SPICE modeling parameters.
Central Semiconductor JFET Paramtric Search Page: Central Semiconductor offers a variety of JFETs. At this link find its JFETs and associated electrical specifications.
Microsemi via Microchip: Microsemi was acquired by Microchip, a public company. Although Microsemi’s JFET overview page still exists, at last check, no details about its JFET products are available.
Digitron Corportion JFET Page: Digitron has been providing engineering services since 1977. This page indicates that it has a high reliability JFET device available ,the 2N4860..
NASA JFET IC Tech Guide: NASA, the National Aeronautics and Service Administration, offers SiC JFET design, license and fabrication technology. This page includes numerous papers on the use, licensing and its manufacturing process flow(prototype NASA Glenn JFET IC wafer runs). Its an ideal resource for those wanting to enter the SiC JFET market. SiC JFETs, unlike your classical silicon JFET are used for very high power applications
Epiworld International SiC JFET Page: According to this link, Epiworld, a joint venture based in China, provides SiC epitaxial foundry services. Specifically, standard 4H-SiC epitaxial wafers of 3″ , 4″and 6″ for Schottky diodes, MOSFETs, JFETs, and BJTs
Micross: Micross provides die, wafer and add on services for JFET and other semiconductor devices. It provides these services to JFET companies like InterFet and Linear Integrated Systems.
Further complicating market analysis is that it is hard to discern if specific companies are still in the discrete JFET market. For example, one will find Toshiba JFETs sold through distributors, however there is no indication that Toshiba still manufacturers discrete JFETs or for that matter, if another company obtained rights to manufacture and sell them underneath the Toshiba name. Other question marks abound about Japanese JFET operations. More so, another complicating factor is that distributors may still have inventories of JFET parts produced years ago.
Some market research firms also include Silicon Carbide (SiC) JFETs in their JFET market totals. Technically a SiC JFET, unlike your classical 1960s JFET, is used in very high power applications and in very high temperature environments. As a point in contrast, your classical 1960s JFET besides audio and sensor applications is often used in sophisticated supercooled applications.
The JFET Tomorrow
Despite the advances in digital signal processing to compensate for noise and temperature, today’s 60 year old discrete JFET technology is still hard to compete with in terms of performance and cost. Audio engineers still attest to the JFET’s quality as a front-end preamplifier. As well, those that design front-end electronics equipment, consider yesterday’s JFET vital for interfacing to sensors for thousands of different IoT applications.
Still though the move to integrate discrete JFETs into mainstream digital chips and mixed signal chips continues. Because, JFETs are often used to interface directly with photodetectors, instrumentation manufacturers want to be able to integrate the JFET and photodetectors into digital systems. For the most part, this goal has been hard to achieve because of the costs and the volume requirements. Most instrumentation applications are not high volume or at least not high enough in volume to substantiate the extra cost of integrating a JFET into a digital or mixed signal chip. There there is the performance losses associated with JFET chip integration. JFETs don’t scale well like MOSFET digital based transistors. You won’t see a nanometer JFET transistor. A JFET has properties that are more analog than their digital MOSFET transistors. When you scale a JFET it loses its analog properties. Even with that, JFETs can be used to construct logic circuits.
Its hard to discern if the classical JFET will be on the shopping shelves tomorrow. The SiC JFET no doubt will be. In the future it could be that one has to custom order classical JFETs to ensure volume size shipments.
About the IP Core Matrix
The IPCore Matrix short course on-a-poster, below, summarizes IP core used in neural network based artificial intelligence applications. JFETs can also be used to prototype neural network based circuit designs.
Applications
