Thin-film characterization instrument using an updated van der Pauw method

Date

4-1993

Degree

Bachelor of Science in Applied Physics

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Demetrio A Yco, Jr.

Abstract

An instrument has been developed for thin-film characterization at the temperature range 80-300K. Using the constructed apparatus, two direct gap semiconductor samples, indium phosphide (InP) and indium antimonide (InSb) were characterized by resistivity and Hall effect measurements. An updated van der Pauw method which implements the contact permutation averaging technique and the Newton-Raphson iterative computation was used for the measurements. The majority charge carrier mobilities and concentrations were computed using the said measurements. The InP and InSb samples showed contrasting resistivities at the 80-300K temperature range. InSb sample was found to have a maximum resistivity at T = 100.8K where P= 1.461 x 10-1 52 cm while the InP sample showed a minimum resistivity of 6.67 x 10-4 2 cm at T = 200K. Semiconductor to metallic property transition was observed only for the InP sample. The Hall coefficients generally decreased as temperature was increased. InSb showed a high IRhI = 7.8 x 103 cm3/A.s at T = 78.8K and lnP, 0.812 cm3/A.s at T = 103.8. The majority carrier concentration of the InP sample was found to be higher than that of InSb. 1nSb

exhibited a 1014 cm-3. carrier degeneracy at 78K where n = 8 x The concentration increased as temperature increased from T = 150K to 300K. A high carrier concentration (n = 8.68 x 1018 cm-3) was found at T = 299.7K for the lnP sample, revealing its metallic property at this temperature range. The 1nSb sample had a very high mobility of 81,836 cm3/A.s at 175.6K. From this point, mobility decreased as temperature increased, a characteristic of low-doped semiconductor samples where p e T-2.3±0.1 over a certain temperature range. A peak mobility of 1203 cm2/V.s was recorded at T = 103.8K for the InP samples. The mobility of InP also decreased as temperature increased. Thus, the constructed instrument using the updated van der Pauw method revealed somehow the contrasting electronic properties of two very important III-V compound semiconductors, InSb and InP.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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