Polycrystalline silicon raw material for photovoltaic power generation and silicon wafer for photovoltaic power generation

摘要

Polycrystalline silicon for use in solar energy production is produced by passing silane gas over a heated silicon seed rod in a sealed reactor at high temperature. The gas is thermally decomposed or reduced with hydrogen to produce a material with p- or n-conductivity, a specific resistance of 3 -500 ohm-cm and a life of 2 - 500 microseconds. Independent claims are included for: (A) silicon chips produced by crystallization of the polycrystalline material without adding a dopant; (B) a method for making the polycrystalline material, as described; and (C) a method for making the polycrystalline material using a seed rod made from the polycrystalline material with an internal heat source and a second heat source made from a metal or alloy with a recrystallization temperature of 1100[deg]C or more or from graphite.