Resistance circuit, oscillation circuit, and in-vehicle sensor apparatus

An oscillation circuit comprising:

• a semiconductor substrate;
• a capacitor that is formed on a principal surface of the semiconductor substrate;
• and
• a resistance circuit that is formed on the principal surface of the semiconductor substrate,
• an oscillating frequency of the oscillation circuit being set by a capacitance value of the capacitor and a resistance value of the resistance circuit, wherein
• the resistance circuit includes:
• an N-type resistance section that is formed on the principal surface of the semiconductor substrate;
• and
• a P-type resistance section that is formed on the principal surface of the semiconductor substrate and that is electrically connected in series to the N-type resistance section,
• the N-type resistance section has a first N-type diffusion layer resistance element and a second N-type diffusion layer resistance element that are disposed to form a right angle with respect to each other and that are electrically connected in series,
• the P-type resistance section has a first P-type diffusion layer resistance element and a second P-type diffusion layer resistance element that are disposed to form the right angle with respect to each other and that are electrically connected in series,
• the first N-type diffusion layer resistance element is disposed along a second crystal orientation direction of the semiconductor substrate, the second crystal orientation direction being different from a first crystal orientation direction of the semiconductor substrate, the first crystal orientation direction being a direction in which a stress sensitivity based on a piezoresistance coefficient becomes maximum, and
• the first P-type diffusion layer resistance element is disposed along a direction different from the second crystal orientation direction.

An in-vehicle sensor apparatus comprising:

• a semiconductor chip that includes an oscillation circuit having an oscillating frequency set by a capacitance value of a capacitor and a resistance value of a resistance circuit;
• a sensor element that includes a detection section detecting an electrical characteristic in response to a physical quantity;
• a chip package that encapsulates the semiconductor chip and the sensor element by a first resin in such a manner as to make the detection section into an exposed state;
• and
• a housing that encapsulates part of surroundings of the chip package by a second resin in such a manner as to make the detection section into the exposed state, wherein
• the oscillation circuit includes:
• a semiconductor substrate;
• the capacitor that is formed on a principal surface of the semiconductor substrate;
• and
• the resistance circuit that is formed on the principal surface of the semiconductor substrate,
• the resistance circuit includes:
• an N-type resistance section that is formed on the principal surface of the semiconductor substrate;
• and
• a P-type resistance section that is formed on the principal surface of the semiconductor substrate and that is electrically connected in series to the N-type resistance section,
• the N-type resistance section has a first N-type diffusion layer resistance element and a second N-type diffusion layer resistance element that are disposed to form a right angle with respect to each other and that are electrically connected in series,
• the P-type resistance section has a first P-type diffusion layer resistance element and a second P-type diffusion layer resistance element that are disposed to form the right angle with respect to each other and that are electrically connected in series,
• the first N-type diffusion layer resistance element is disposed along a second crystal orientation direction of the semiconductor substrate, the second crystal orientation direction being different from a first crystal orientation direction of the semiconductor substrate, the first crystal orientation direction being a direction in which a stress sensitivity based on a piezoresistance coefficient becomes maximum, and
• the first P-type diffusion layer resistance element is disposed along a direction different from the second crystal orientation direction.