In order to contextualise the main work a general overview of surface engineering technology is given. There follows a detailed account of current state of play in sputter magnetron design, the coatings which can be grown and their properties. Next the magnetic field surrounding a two dimensional magnet is described. This allows a check on the subsequent derivation of an equation in integral form which in principle enables the calculation of the magnetic field associated with any simple (usually one ferromagnetic component) magnetron whose geometry may be regarded as being two dimensional. The equation is arrived at using conformal mapping techniques. It is used to find analytic expressions for the magnetic stream function and the magnetic field for the 'standard' rectangular magnetron geometry. General behaviour of sputter magnetrons as a function of magnetic field is discussed. Theoretical results are given for a commercial planar magnetron and these are supported by experiment. The results are used to calculate the effective potential well as seen by electrons in the vicinity of this device. Some device characterisation is included. Theory, design, construction and performance of a magnetron system based on the Penning geometry is described. This apparatus is referred to as the Dimag. It is retrofitted to an existing high vacuum facility. This system is then used to produce Carbon Nitride coatings with approximately 39 atomic percent Nitrogen incorporation.