ON THE PRESSURE LIMITS OF DIAMOND CHEMICAL-VAPOR-DEPOSITION

A detailed examination of proposed diamond growth mechanisms was perfo rmed. Within the framework of existing models, a simple argument is pr esented to explain the experimentally observed limits to diamond growt h by chemical vapor deposition (CVD) at pressures below 1 Torr. Based on data from a variety of conventional CVD reactors it is suggested th at the CVD of diamond is not possible in systems where the partial pre ssure of atomic hydrogen is less than 20 mTorr. The addition of oxygen appears to depress the pressure limit by a factor of 10, which is att ributed to the presence of hydroxyl radicals that remain active at low er growth temperatures.