Studies of magnetoresistance and hall sensors in semiconductors
<p>The design, fabrication and performance of an Extraordinary Magnetoresistance (EMR) and a Vertical Mesa Hall Sensor (VMHS) are studied.</p> <p>EMR devices have been fabricated from a 2DEG InAs/GaSb structures which exhibit a low carrier density and high mobility that achieve the...
| Main Authors: | , |
|---|---|
| Other Authors: | |
| Format: | Thesis |
| Language: | English |
| Published: |
2006
|
| Subjects: |
| _version_ | 1797070036984135680 |
|---|---|
| author | Wipatawit, P P. Wipatawit |
| author2 | Nicholas, R |
| author_facet | Nicholas, R Wipatawit, P P. Wipatawit |
| author_sort | Wipatawit, P |
| collection | OXFORD |
| description | <p>The design, fabrication and performance of an Extraordinary Magnetoresistance (EMR) and a Vertical Mesa Hall Sensor (VMHS) are studied.</p> <p>EMR devices have been fabricated from a 2DEG InAs/GaSb structures which exhibit a low carrier density and high mobility that achieve the best performance. The general electrical magneto-transport properties are given. The experiments investigate mainly different metallic patterns, which are Rectangular, Triangular and Tip pattern between 4-300 K. Probe configurations and the enhancement of relative size of metallic patterns are described. EMR effect is due to current deflection around the metal-semiconductor interface. The results are metallic pattern dependent. Using finite element analysis, good agreement between experimental and theoretical results was found. The best performance sensor is a symmetrical metallic Tip pattern. It is enhanced by the length of the Tip’s point and the large metallic area. This pattern when combines with an asymmetrical probe configuration, exhibits the highest EMR of 900% at –0.275T measured by inner probes and the best sensitivity of 54Ω/T at room temperature. </p> <p>The second study presents in-plane Hall effect sensors made from InSb. A simple device geometry has been used in which current flows in a plane perpendicular to the device surface. Device sensitivity depends on its geometry and a series of different contacts are used to investigate the geometry of the current flow distribution. The structures produced are only sensitive to the presence of one in-plane field component, and they also demonstrate good angular selectivity. Multi-electrodes were used to investigate biasing current from both mesa and substrate condition. We are able to examine the Hall voltage as a function of contact positions and also to create multiple VMHS. Offset reduction of devices has been achieved by moving the ground contacts to re-balance the current distribution under the mesa surface.</p> |
| first_indexed | 2024-03-06T22:33:17Z |
| format | Thesis |
| id | oxford-uuid:58faf6f4-debb-4695-8909-fca7cbf310a2 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T22:33:17Z |
| publishDate | 2006 |
| record_format | dspace |
| spelling | oxford-uuid:58faf6f4-debb-4695-8909-fca7cbf310a22022-03-26T17:07:09ZStudies of magnetoresistance and hall sensors in semiconductorsThesishttp://purl.org/coar/resource_type/c_db06uuid:58faf6f4-debb-4695-8909-fca7cbf310a2Condensed Matter PhysicsEnglishOxford University Research Archive - Valet2006Wipatawit, PP. WipatawitNicholas, R<p>The design, fabrication and performance of an Extraordinary Magnetoresistance (EMR) and a Vertical Mesa Hall Sensor (VMHS) are studied.</p> <p>EMR devices have been fabricated from a 2DEG InAs/GaSb structures which exhibit a low carrier density and high mobility that achieve the best performance. The general electrical magneto-transport properties are given. The experiments investigate mainly different metallic patterns, which are Rectangular, Triangular and Tip pattern between 4-300 K. Probe configurations and the enhancement of relative size of metallic patterns are described. EMR effect is due to current deflection around the metal-semiconductor interface. The results are metallic pattern dependent. Using finite element analysis, good agreement between experimental and theoretical results was found. The best performance sensor is a symmetrical metallic Tip pattern. It is enhanced by the length of the Tip’s point and the large metallic area. This pattern when combines with an asymmetrical probe configuration, exhibits the highest EMR of 900% at –0.275T measured by inner probes and the best sensitivity of 54Ω/T at room temperature. </p> <p>The second study presents in-plane Hall effect sensors made from InSb. A simple device geometry has been used in which current flows in a plane perpendicular to the device surface. Device sensitivity depends on its geometry and a series of different contacts are used to investigate the geometry of the current flow distribution. The structures produced are only sensitive to the presence of one in-plane field component, and they also demonstrate good angular selectivity. Multi-electrodes were used to investigate biasing current from both mesa and substrate condition. We are able to examine the Hall voltage as a function of contact positions and also to create multiple VMHS. Offset reduction of devices has been achieved by moving the ground contacts to re-balance the current distribution under the mesa surface.</p> |
| spellingShingle | Condensed Matter Physics Wipatawit, P P. Wipatawit Studies of magnetoresistance and hall sensors in semiconductors |
| title | Studies of magnetoresistance and hall sensors in semiconductors |
| title_full | Studies of magnetoresistance and hall sensors in semiconductors |
| title_fullStr | Studies of magnetoresistance and hall sensors in semiconductors |
| title_full_unstemmed | Studies of magnetoresistance and hall sensors in semiconductors |
| title_short | Studies of magnetoresistance and hall sensors in semiconductors |
| title_sort | studies of magnetoresistance and hall sensors in semiconductors |
| topic | Condensed Matter Physics |
| work_keys_str_mv | AT wipatawitp studiesofmagnetoresistanceandhallsensorsinsemiconductors AT pwipatawit studiesofmagnetoresistanceandhallsensorsinsemiconductors |