Very-large-scale integration (VLSI) is the process of creating an integrated circuit (IC) by combining thousands of transistors into a single chip. VLSI began in the 1970s when complex semiconductor and communication technologies were being developed. The microprocessor is a VLSI device. Before the introduction of VLSI technology most ICs had a limited set of functions they could perform. An electronic circuit might consist of a CPU, ROM, RAM and other glue logic. VLSI lets IC designers add all of these into one chip.
Race is going on to make the devices as small as possible with highest possible efficiency and low power. For this you surely need smallest possible IC with lot many peripherals in it. But at the same time, power consumption should be low. Take any of the high end micro controller IC and see what all peripherals are into it. ADC, DAC, Communication protocols(SPI, I2C, Serial, Ethernet etc), timers, crystal oscillators, variety of clock systems etc. For designing such ICs, think for yourself as how much VLSI has gone far to develop these. Vast scope in this field too.