We have used transmission electron microscopy and low temperature photoluminescence to study the growth by chemical beam epitaxy of self-assembled InAs/InP quantum dots as a function of growth interruption time. As the deposited InAs layer is given time to migrate on the semiconductor surface a number of different features appear. The InAs layer first forms a rough quantum well with monolayer fluctuations in width before forming elongated InAs islands. These islands are elongated along the [01-1] direction due to surface diffusion dynamics. These then break up into individual quantum dots, and slowly increase in height. These dots are found to be approximately square with their sides aligned along the (100) directions and lateral dimensions of 30-40 nm.