"But i am interested in MCU which can build system with minimum or no external hardware."

Try ATMEL AT89C51/52 for 40pin DIP or AT89C4051 for 20pin DIP. It cost you about $1.5 in price. They have 4kbyte internal flash program memory and the same MCS51 architecture. The only added hardware you need is MAX232 if you need a serial communicaton.