The orientation of ring hexavacancies, namely, the V6 vacancy clusters (B804 centres), in single-crystal Si was investigated under tension. It was demonstrated that hexavacancies under tension of the crystal along the [111] crystallographic direction were oriented in the [¯111], [¯1¯11], and [1¯11] directions. This orientation was explained by the reversal of the sign of the relative change in the length of the 〈110〉 bonds in V6 hexavacancies under tension of the crystal along the [111] direction with respect to the case of compression along the same direction. The pressure dependences of the intensity ratio I1/I2 of the lines X804 (J1) and X724 (J2) in the spectrum of the recombination radiation of excitons bound to the V6 hexavacancies were obtained. These dependences characterize the degree of orientation of the V6 hexavacancies as a function of the pressure acting on the V6 hexavacancies under compression and tension of the Si crystal. A method was proposed for the orientation of V6 hexavacancies in the case of simultaneous compression and tension of the crystal under bending.

Orientation of Ring Hexavacancies under Bending of Silicon Crystals. A.S.Kaminskii: Physics of the Solid State, 2007, 49[5], 851-7