Formation of deep holes in silicon by reactive ion etching

Anisotropic etching for the formation of deep holes in the single crystalline silicon has been reported. This technique uses a film deposited on the sidewall to inhibit the lateral etching caused by the bombardment of ions which impinge on the silicon substrate out of the vertical direction. This film is composed of materials released from the cathode plate by ion bombardment. Using this technique, profiles appropriate for refilling with chemical vapor deposited CVD polycrystalline silicon can be obtained by adjusting the ratio of film deposition rate to silicon etch rate. It was found that this ratio can be controlled by adjusting parameters in reactive ion etching, such as self-bias voltage Vdc and gas pressure.