EPROM (Erasable Programmable Read-Only Memory) is a type of non-volatile memory that can be electrically programmed and erased for multiple times. It is widely used in various electronic devices for data storage.

EPROM Erasure Mechanism:
EPROM is generally erased using ultraviolet (UV) rays. The erasure mechanism involves the use of UV light to remove the charge that has been trapped in the floating gate transistor. The floating gate transistor is the key component of an EPROM cell, which stores the data in the form of trapped electrical charge.

Explanation:
EPROM cells are made up of MOS (Metal-Oxide-Semiconductor) transistors, which consist of a floating gate and a control gate. The floating gate is isolated from the rest of the transistor by a thin insulating oxide layer. When a voltage is applied to the control gate, the charge is stored in the floating gate, causing the transistor to be in either a programmed (charged) or erased (discharged) state.

To erase the stored data in an EPROM, it needs to be exposed to UV light. The UV light has a shorter wavelength than visible light, and it is capable of penetrating the quartz window on top of the EPROM package. The photons in the UV light have enough energy to excite the electrons in the floating gate, allowing them to escape from the oxide layer. This process is known as the Fowler-Nordheim tunneling.

The UV light exposure removes the charge from the floating gate, effectively erasing the data stored in the EPROM. Once the data is erased, the EPROM can be reprogrammed by applying the appropriate voltage to the control gate and injecting electrons into the floating gate.

Advantages of UV Erasure:
1. Non-destructive: The UV erasure process does not damage the EPROM cells, allowing them to be reprogrammed and reused.
2. Selective Erasure: UV light can erase specific EPROM cells without affecting others, allowing targeted modifications to the data.

Limitations of UV Erasure:
1. Exposure Time: The EPROM needs to be exposed to UV light for a certain duration to ensure complete erasure. This can be time-consuming compared to other erasure methods.
2. Window Requirement: EPROM packages need to have a quartz window on top to allow UV light to pass through. This adds complexity and cost to the EPROM packaging.

In conclusion, EPROM is generally erased using ultraviolet (UV) rays. The UV light removes the charge from the floating gate transistor, effectively erasing the stored data. This UV erasure process allows the EPROM to be reprogrammed and reused multiple times.