A detailed cross section of DRAM is presented in this book. DRAM is abbreviation of Dynamic Random Access Memory. DRAM is volatile memory used for electronic devices such as personal computer, cell phone, pad, etc. DRAM (Dynamic Random Access Memory) becomes an important component for electronic devices is after Bill Gates and Paul Allen found Microsoft Corporation which makes the personal computer software operation system DOS (disk operation system) in 1975.Nowadays, the memory unit is improved and has a lot of progress from K (kilobyte or KB) to G (gigabyte or GB). The DRAM memory IC is a key component of personal computer and the price of it is lower than that of the CPU IC.