Hayghtening or Heightening: How To spell?

The word Hayghtening is misspelled against Heightening, which is present continuous of "Heighten"

Word contains consecutive vowels 'EI' in between alphabets h & ghtening is misspelled as 'AY'
Wrong Spelling:  h-ay-ghtening 
Correct Spelling:  h-ei-ghtening 
Find more wrongly spelled words of Heightening to spell it well.