Wafer & EPROM Erasers

The expertise in ultraviolet light source manufacturing Jelight Company has gained throughout the years has assisted us in designing UV Wafer and EPROM Erasers with superior performance and productivity. Our high intensity UV lamp design is at least 25% greater than competitive systems for increased output. Excellent uniformity also ensures a fast and complete erasure.

How Do Wafer Erasers/EPROMs Work?

The basic memory element was developed by Frohman-Bentchkowsky at Intel Corporation and was known as the Floating-Gate-Avalanche-Injection MOS (FAMOS) transistor. It was essentially a silicon gate MOS field effect transistor, in which no connection was made to the gate. The gate was in fact electrically “floating” in an insulating layer of silicon dioxide. The devices have been fabricated in two structures: p-channel and n-channel. The p-channel devices were the first EPROMs available commercially, but many devices are now using n-channel technology. N-channel MOS devices have the advantage of being able to function with a single power supply.

By application of a sufficiently large potential difference between the source and drain, charge can be injected into the “floating” gate which induces a charge in the substrate. The source-to-drain impedance changes and a “p-channel” or “n-channel” is created, depending upon the type of substrate. The presence or absence of conduction is the principle of data storage. Application of short wave (254 nm) ultraviolet radiation causes the gate charge to leak away and restores the device to its original un-programmed state. EPROM manufacturers provide “nominal erasing energies” to their devices; that is the amount of UV energy required to erase a chip’s memory. Erasing time can be calculated using following formula:  

Most Wafer Erasers have a nominal erasing energy of 15W-sec/cm². However, for complete erasure, some chips require as little as 6 or 10W-sec/cm², or as much as 25W-sec/cm².

Below is a picture of our Model 2442 with some 8″ [203 mm] wafers for scale.


  • Quick load/unload trays for wafers and EPROM.
  • All-metal housing.
  • Heavy duty construction for longevity.
  • Stackable to save space.
  • Safety interlocks to prevent accidental UV exposure.

Jelight Company can also manufacture customized products, including: Conveyor belt systems, Wafer Erasers of larger capacities, cassette to cassette erasing systems, additional trays, and radiometers.

Model List

Please click the box below for a complete list of models offered:

Erasing Capability: Chips/Hour

  • At 6 W-sec/cm2: 11,250 to 45,000.
  • At 10 W-sec/cm2: 5,985 to 23,940.
  • At 15 W-sec/cm2: 4500.