Abstract: A method of programming a flash memory cell which increases programming efficiency and characteristics. A depletion area formed at a source region is extended from a surface portion of a silicon substrate to the bottom portion of the silicon substrate. A minority carrier produced at a trap center existing at the extended depletion area receives energy from a high electric field area formed at the silicon substrate between a select gate and floating gate. The minority carrier is then changed into a hot electron by a voltage applied to a drain region. The electron is injected into a floating gate by a vertical direction electric field formed by a high potential voltage applied to a control gate.