Diode-based thermal r.m.s. converter with on-chip circuitry fabricated using CMOS technology
| Autor: | Erno H. Klaassen, R.J. Reay, Gregory T. A. Kovacs |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
Silicon
business.industry Chemistry Dynamic range Thermal resistance Metals and Alloys Electrical engineering chemistry.chemical_element Condensed Matter Physics Surfaces Coatings and Films Electronic Optical and Magnetic Materials law.invention Surface micromachining CMOS law Optoelectronics Undercut Electrical and Electronic Engineering Resistor business Instrumentation Diode |
| Zdroj: | Sensors and Actuators A: Physical. 52:33-40 |
| ISSN: | 0924-4247 |
| DOI: | 10.1016/0924-4247(96)80122-1 |
| Popis: | A high-frequency root-mean-square (r.m.s.) converter composed of two matched thermal elements and on-chip circuitry has been fabricated in a foundry CMOS process with post-process micromachining techniques. An anisotropic undercut etch in conjunction with an electrochemical etch stop is used to form the thermal elements of the r.m.s. converter, which are suspended single-crystal silicon regions containing temperature-sensing diodes heated by polysilicon resistors. One of the elements is heated by the a.c. signal, while an integrated continuous-time feedback network maintains a second element at the same temperature. The converter has a packaging-limited — 3 dB bandwidth of 415 MHz, an r.m.s. dynamic range of 53 dB, nonlinearity of 1%, a quiescent power dissipation under 1 mW, and occupies an area of approximately 400 μm × 400 μm. The thermoelements have a thermal resistance of up to 37 000 K W −1 in air. In addition to the r.m.s. converter itself, an improved wet etchant chemistry is presented. Ammonium persulfate, when added to tetramethyl ammonium hydroxide (TMAH) silicon etchant, improves the silicon etch rate and the (100) surface quality. This etch chemistry should be useful for a broad range of CMOS-compatible micromachining applications. |
| Databáze: | OpenAIRE |
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