A system for generating a multiple phase clock is provided. The system includes a ring oscillator structure for generating multiple phases. The structure includes two or more unit oscillators, each unit oscillator implemented by a ring oscillator having M stages. The structure also includes a horizontal loop coupling the two or more unit oscillators to generate multiple phases. The number of phases generated is equal to the product of the number of unit oscillators and M. Another structure generates multiple phases using a multi-dimensional oscillator including ring oscillators constructed as vertical and horizontal loops with shared elements between the oscillators. A memory system includes a ring oscillator structure with vertical and horizontal loops, the ring oscillator structure receiving an input clock and outputting a multiple phase clock to one or more of a memory controller, memory devices and a memory interface device.