The impurity heterogeneities in the surface layer of silicon with an atomically clean surface

The electrical and photoelectrical properties of the surface region of silicon after evaporation in vacuum used in obtaining an atomically clean surface at the subsequent epitaxy are studied. The formation kinetics of a p-layer at 1300 and 1350 °C for the heating time of 10 to 10³ s is investigated. The effective values of holes mobility in p-layers are independent on a decrease of layer thicknesses down to 0.2μm at the concentration of acceptors of 10¹⁷ to 10¹⁸ cm⁻³ (294 K). The concentrations of doping impurities in the surface region of silicon before and after thermal treatment are determined by the method of mass-spectrometric analysis. The peculiarities of transport and building-in of doping impurities of the III and V groups at epitaxy and the possible nature of acceptor levels are discussed. A concentration profile of acceptors and donors from the surface deep into the silicon bulk is determined by the methods of layer-by-layer etching and of C-V characteristics. An effective built-in electric field is due to acceptor and donor distribution, which favours drift separation of minor radiation-generated current carriers in the p-n structure. The high-sensitive and fast-responding photoreceivers have been produced. The given detectability reaches 2 × 10¹² cm Hz^1/2/W at a wavelength of 1.06μm.