{HEAD ~ The impurity layer} of high impurity concentration is formed between {TAIL ~ the first semiconductor substrate} and the epitaxial layer 
is formed between
{ HEAD ~ The impurity layer } of high impurity concentration is formed between { TAIL ~ the first semiconductor substrate } and the epitaxial layer
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH