Carbon-14 (14C) is produced via a nuclear reaction between the atmosphere and cosmic rays. Although the main source of 14C is galactic cosmic rays, solar energetic particles (SEPs) also contributes in producing 14C. Extreme SEP events are considered to produce 14C spikes that considerably exceed the 14C amount produced by galactic cosmic rays. Thus far, several signatures of 14C spikes originates by extreme SEP events have been reported, such as the 774 CE, 992 CE, and ~660 BCE events. In this presentation, the detected 14C spikes and a further survey of past SEP events will be introduced.