Semiconductor pressure sensor and manufacture thereof

Abstract

Abstract PURPOSE:To obtain diaphragms excellent in uniformity by a method wherein a B-added layer is previously provided in an Si substrate and made as an etching stopped layer, its concentration being selected so as to provide moderate lattice defects, and anisotropic etching being then performed at a low speed with N2H4H2O or the like. CONSTITUTION:A layer 6 containing B at 5-10<18>-5X10<19>/cm<3> and an N<-> layer 7 are epitaxially grown on the (100) surface of an N<-> type single crystal Si, and a P type diffused resistor 3 and a P<+> type diffused lead 8 are formed on the surface, further an N<-> epitaxial layer 9 is superposed. It is covered with an Si3N4, which is then provided with an aperture, and an Al layer 5 is attached to the lead. Next, when etching is performed with a solution containing N2H4H2O as the main constituent, the shape around a diaphragm 2 can be formed with high accuracy and good reproducibility because the etching rate in the (100) direction is much higher than in the (111) direction. Since the B concentration of the layer 6 serving as the etching stopper layer is restricted, lattice defects do not come to excess, and stable formation can be carried out particularly by the epitaxial method while a good mechanical strength is kept. Accordingly, the titled device of high accuracy excellent in the uniformity and the pressure resistance of the diaphragm in the pressure reception part can be obtained.

Inventors

• 👤 Katsunori Nishiguchi
• 👤 勝規 西口
• 👤 Junichi Hiramoto
• 👤 順一 平本
• 👤 Toshiki Ehata
• 👤 敏樹 江畑

Bibliographic Details