EVALUATION OF AN EPITAXIAL LAYER STRUCTURE BY LATERAL FORCE AND CONTACT CURRENT MEASUREMENTS IN A SCANNING FORCE MICROSCOPE

The evaluation of an epitaxial layer structure has been demonstrated b y means of lateral force and contact current measurements, using a for ce microscope under ambient air condition. The specimen was an MOVPE g rown n-doped InP layer on semiinsulating InP that was prepared with an ohmic contact on one side. Lateral force measurements showed a contra st between n-doped and semiinsulating layer whereas the corresponding axial mode image did not. The microscope was equipped with a conductin g tip to perform contact current measurements. Both DC and AC measurem ents showed a strong contrast in conductivity even under bad topograph ical conditions.