Borophosphosilicate glass, commonly known as BPSG, is a type of silicate glass that includes additives of both

boron Boron is a chemical element; it has symbol B and atomic number 5. In its crystalline form it is a brittle, dark, lustrous metalloid; in its amorphous form it is a brown powder. As the lightest element of the boron group it has three ...

and

phosphorus Phosphorus is a chemical element; it has Chemical symbol, symbol P and atomic number 15. All elemental forms of phosphorus are highly Reactivity (chemistry), reactive and are therefore never found in nature. They can nevertheless be prepared ar ...

. Silicate glasses such as PSG and borophosphosilicate glass are commonly used in

semiconductor device fabrication Semiconductor device fabrication is the process used to manufacture semiconductor devices, typically integrated circuits (ICs) such as microprocessors, microcontrollers, and memories (such as Random-access memory, RAM and flash memory). It is a ...

for intermetal layers, i.e., insulating layers deposited between succeedingly higher metal or conducting layers. BPSG has been implicated in increasing a device's susceptibility to

soft error In electronics and computing, a soft error is a type of error where a signal or datum is wrong. Errors may be caused by a defect, usually understood either to be a mistake in design or construction, or a broken component. A soft error is also a ...

s since the boron-10 isotope is good at capturing

thermal neutron The neutron detection temperature, also called the neutron energy, indicates a free neutron's kinetic energy, usually given in electron volts. The term ''temperature'' is used, since hot, thermal and cold neutrons are moderated in a medium wit ...

s from

cosmic radiation Cosmic rays or astroparticles are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Sol ...

.An Accurate and Comprehensive Soft Error Simulator Y. Tosaka, S. Satoh, and H. Oka - Fujitsu Laboratories
/ref> It then undergoes fission producing a

gamma ray A gamma ray, also known as gamma radiation (symbol ), is a penetrating form of electromagnetic radiation arising from high energy interactions like the radioactive decay of atomic nuclei or astronomical events like solar flares. It consists o ...

, an

alpha particle Alpha particles, also called alpha rays or alpha radiation, consist of two protons and two neutrons bound together into a particle identical to a helium-4 nucleus. They are generally produced in the process of alpha decay but may also be produce ...

, and a

lithium Lithium (from , , ) is a chemical element; it has chemical symbol, symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard temperature and pressure, standard conditions, it is the least dense metal and the ...

ion. These products may then dump charge into nearby structures, causing data loss (bit flipping, or single event upset). In critical designs, depleted boron consisting almost entirely of boron-11 is used to avoid this effect as a

radiation hardening Radiation hardening is the process of making electronic components and circuits resistant to damage or malfunction caused by high levels of ionizing radiation (particle radiation and high-energy electromagnetic radiation), especially for environm ...

measure. Boron-11 is a by-product of the nuclear industry.

References

Semiconductor device fabrication Glass compositions Boron compounds {{Glass-material-stub